Summary

What makes women and men different in terms of love.

Evolutionary reasons for love:

The primary reason many psychologists and biologist think we have developed capacity for love is that human children are dependent on their parents for a very long time, so in order to ensure their survival humans, both male and female had to stay together. ^1

Love Biology

When looking at love from a biological point of view we have to distance ourselves from concepts that are rooted in philosophical aspects, culture or norms. Love is primarily a biological thing, love doesn’t exist without it and love isn’t defined outside of it, you can’t love something philosophically or thinking about something won’t produce a feeling your incapable of in terms of human nature, for all we know somewhere out there exists a species that is as intelligent as we are but their biology is incapable of love for reasons unknown.
Love is chemical, it’s not something mysterious, or holy, men aren't better at it nor capable of more love than women biologically speaking, but their perception, understanding and definition of love is different. Men and women percieve and value love differently.

Love as micro-moments:

Fredrickson, a leading researcher of positive emotions at the University of North Carolina at Chapel Hill, presents scientific evidence to argue that love is not what we think it is. It is not a long-lasting, continually present emotion that sustains a marriage; it is not the yearning and passion that characterizes young love; and it is not the blood-tie of kinship.

Rather, it is what she calls a "micro-moment of positivity resonance." She means that love is a connection, characterized by a flood of positive emotions, which you share with another person—any other person—whom you happen to connect with in the course of your day. You can experience these micro-moments with your romantic partner, child, or close friend. But you can also fall in love, however momentarily, with less likely candidates, like a stranger on the street, a colleague at work, or an attendant at a grocery store.

You have to physically be with the person to experience the micro-moment. For example, if you and your significant other are not physically together—if you are reading this at work alone in your office—then you two are not in love. You may feel connected or bonded to your partner—you may long to be in their company—but your body is completely loveless.

To understand why, it's important to see how love works biologically. Like all emotions, love has a biochemical and physiological component. But unlike some of the other positive emotions, like joy or happiness, love cannot be kindled individually—it only exists in the physical connection between two people. Specifically, there are three players in the biological love system—mirror neurons, oxytocin, and vagal tone. Each involves connection and each contributes to those micro-moment of positivity resonance that Fredrickson calls love. ^3

Research has concluded, without a doubt that a person responds with their entire body when they feel desire. As stated earlier, when one is around an object of their desire, adrenaline is released, at least in the early stages. Adrenaline, also known as epinephrine, which is both a neurotransmitter and hormone, is released from the adrenal medulla during the “fight or flight response.

Epinephrine:
Epinephrine is released in both love and in ”fight or flight” mode, it’s why we feel like a deer in headlights when we experience love at first sight a.k.a instant attraction.

Endorphin:
The feel-good chemical, is produced during sex and during exercise, hence why lifting is so important, it’s a chemical your body craves, one of the reasons many say they HAVE to exercise. Endorphins are also released by touch, this is where kino comes in when we talk about game. When people talk about falling in love, this is the love drug. ^4

Oxytocin:
The bonding hormone, and also the one where males and females differ the most in terms of love. Oxytocin, also known as the “cuddle chemical”, “plays an important role in romantic love, as a hormone that encourages cuddling between lovers and increases pleasure during lovemaking… The hormone stimulates the smooth muscles and sensitizes the nerves, and snowballs during sexual arousal.”. ^5 Oxytocin is also linked to the feeling of “closeness” that one experiences after intercourse, which may explain why women are statistically more likely to “fall” for a man that they may know they have no future with, yet they mistakenly associate the feeling they experience after the release of oxytocin with love.
Since oxytocin is released through physical touch, including “stroking, cuddling, hugging, kissing, or having sex” ^6 , it can be concluded that it is also associated with the release of other distinct hormones in the body. In fact, “oxytocin works in tandem with other neurotransmitters such as testosterone… oxytocin may also influence how the feel-good neurotransmitters dopamine and norepinepherine hit the reward parts of the brain.”

When both males and females were administered oxytocin, females reacted faster to socially relevant stimuli than males did, that is to say that women are capable of feeling love faster or falling out of love faster than men, more oxytocin can also create fear and anxiety for women because of estrogen. Additionally, after the administration of oxytocin, females show increased amygdala activity in response to threatening scenes. Amygdala is the part of our brain that is in charge of memory, decision-making and emotional reactions. The reason why men don’t reacted the same way is because of estrogen in women. Estrogen has been shown to stimulate the release of oxytocin from the hypothalamus and promote receptor binding in the amygdala. ^7

Estrogen:
The female sex hormones, they are also the most important in terms of a woman’s sexual biology, such as menstrual cycles, breasts, armpit hair, etc. it is also an important part of a woman’s sexual desire, chronically low levels of estrogen are linked with a reduced mood. When a woman stops menstruating her estrogen levels fall off, this why a lot of women are very horny during menstruation. Menopause also severely reduces estrogen levels, biologically speaking there is no point in sex after a woman can’t bear children. Men also produce estrogen but in lower quantities and it is believed to affect sperm count. ^8

Testosterone:

Falling in love decreases men's testosterone levels while increasing women's testosterone levels. There has been speculation that these changes in testosterone result in the temporary reduction of differences in behavior between the sexes. However, it is suggested that after the "honeymoon phase" ends—about one to three years into a relationship—this change in testosterone levels is no longer apparent. Fatherhood also decreases testosterone levels in men, suggesting that the resulting emotional and behavioral changes promote paternal care. Men who produce less testosterone are more likely to be in a relationship and/or married, and men who produce more testosterone are more likely to divorce; however, causality cannot be determined in this relationship. Marriage or commitment could cause a decrease in testosterone levels. Single men who have not had relationship experience have lower testosterone levels than single men with experience. It is suggested that these single men with prior experience are in a more competitive state than their non-experienced counterparts. Married men who engage in bond-maintenance activities such as spending the day with their spouse/and or child have no different testosterone levels compared to times when they do not engage in such activities. Collectively, these results suggest that the presence of competitive activities rather than bond-maintenance activities are more relevant to changes in testosterone levels.

Men who produce more testosterone are more likely to engage in extramarital sex. Testosterone levels do not rely on physical presence of a partner for men engaging in relationships (same-city vs. long-distance), men have similar testosterone levels across the board. Physical presence may be required for women who are in relationships for the testosterone–partner interaction, where same-city partnered women have lower testosterone levels than long-distance partnered women.

It is also the risk taking hormone, and testosterone made the male brain slightly larger than the female. ^9

Conclusions:

The chemicals triggered that are responsible for passionate love and long-term attachment love seem to be more particular to the activities in which both persons participate rather than to the nature of the specific people involved.
When this various cornucopia of hormones and neurotransmitters are released, the body can associate this feeling with love. This is why one may become “attached” to a partner that is absolutely not a good match. Even if one consciously knows that the other person is a bad fit, this cascade of neurotransmitters may confuse the brain into believing the match is compatible. Unfortunately (or fortunately from an evolutionary standpoint), the relationship eventually ends. However, hormones are also extremely important in the feeling of addiction, dopamine especially. Perhaps it is this feeling of “addiction” that keeps couples together.

Love is not ever-lasting, there is no unconditional love (children, family perhaps) and men aren't that different to women when feeling love. Women can love men very very deeply, but the conditions are different and the biology of women makes them fall in and out of love faster. Social conditions also makes it easier for women to do this. To feel love in the biological sense you have to be with your partner, this is why the expression "Out of sight, out of mind" makes sense when speaking about love, thus any heartbreak consists of a combination of;
losing a preferred match—that girl you thought was so hot, she cooked great food, she sucked dick like a pornstar etc.

loss of love chemicals—primarily the "feel-good" ones such as dopamine and endorphin.

sexual desire—testosterone production is higher when single/without a partner, testosterone increases sexual desire, it's why men are much hornier than women in most cases.

If men were somehow capable of true love, never ending love, unconditional love, etc. vis-a-vis women, then most would be alone their whole life and never spread their genes, this is evolutionary suicide. True love is a fairy-tale, it doesn't exist, not for men, not for women. As long as sexual desire exists, they are deemed both preferred matches to each other, love chemicals are being released on a consistent basis, and the couple aren't apart from each other for longer periods of time, then they will and can stay together and even experience love and intimacy. Remember love is biological and only experienced in intimacy and physical closeness, everything else is human thinking and bonding, and even though you may convince a woman to like you based on "biological warfare" she may ditch you if you're not her preferred match (alpha traits?).

Lastly any man with oneities should engage in a lot of physical activity, get those endorphins going, rid himself of anything reminding him of his lost love, if the girl was a good match in his eyes, he should seek a new one (there are plenty). He should also work on himself and develop stronger self love. Give up any thoughts of true romantic love, it doesn't exist, you're not capable of it either for that matter,

Discussion:

I would like to incite a deeper discussion and understanding around the term love for both men and women, also I would like for you to give insights. Feedback is welcomed.

References:

Based on this study: http://digitalcommons.uri.edu/cgi/viewcontent.cgi?article=1218&context=srhonorsprog

1: The Handbook of Evolutionary Psychology, edited by David M. Buss, John Wiley & Sons, Inc., 2005. Chapter 14, Commitment, Love, and Mate Retention by Lorne Campbell B. and Bruce J. Ellis.
2: Sherwood, L. (2006) Fundamentals of physiology: A human perspective. P. 188.
3: http://www.theatlantic.com/sexes/archive/2013/01/theres-no-such-thing-as-everlasting-love-according-to-science/267199/
4: Selhub, E. (2009). The love response. P. 33
5: Ackerman, D. (1994). A natural history of love. P. 163
6: Pincott, J. (2008). Do gentlemen really prefer blondes?: Bodies, behavior and brains- The science behind sex, love & attraction. P. 166
7: https://en.wikipedia.org/wiki/Oxytocin#Fear_and_anxiety_response
8: http://www.livescience.com/38324-what-is-estrogen.html
9: https://en.wikipedia.org/wiki/Testosterone
10: http://www.peplaulab.ucla.edu/Peplau_Lab/Publications_files/Peplau%20%26%20Gordon%2085.pdf p. 263-264 Edit: Formatting.

Based on discussion:

Men and Women differing in love/romance. "Men love sacrificially, women love opportunistically."

/u/CisWhiteMaelstrom Raised a point that while women can love, they can't love the same way a man does, this lead me to finding a study that while neither proving or disproving his statement it actually confirmed some of the assumptions that men are more "romantically " inclined towards long term relationships and marriage, while to women love isn't as important:

"A distinction has frequently been made between romantic versus pragmatic beliefs about love (e.g., Hobart, 1958; Knox & Sporakowski, 1968). The romantic person believes that true love lasts forever, comes but once, is strange and incomprehensible, and conquers barriers of custom or social class. The pragmatist rejects these ideals, knowing that we can each love many people, that economic security is more important than passion, and that some disillusionment surely accompanies marriage. By these criteria, men are apparently more romantic than women. Several studies (e.g., Fengler, 1974; Hobart, 1958; Knox & Sporakowski, 1968; Rubin, 1970; Rubin, Peplau, & Hill, 1981) have found small but consistent sex differences on various romanticism scales. Further evidence comes from responses to questions about the importance of love as a basis for marriage. For example, Kephart (1967) asked students, "If a boy (girl) had all the other qualities you desired, would you marry this person if you were not in love with him/her?" Most of the men (65%) said no, compared to only 24% of the women. Finally, recent research developing a typology of six styles or orientations to love (e.g., Hatkoff & Lasswell, 1979; Lasswell & Lobsenz, 1980; Lee, 1977) further corroborates this picture. Hatkoff and Lasswell ( 1979) found that women were more likely than men to adopt "logical" or "best friends" approaches to love. Men were more likely to be "romantics" who believed in love at first sight, or "game players" who enjoyed flirtation. Intrigued by these findings, social scientists have freely speculated about the reasons for men's greater romanticism. The most common explanation concerns the social and economic context of mate selection. As Waller (1938) explained, "A man, when he marries, chooses a companion and perhaps a helpmate, but a woman chooses companion and at the same time a standard of living. It is necessary for a woman to be mercenary" (p. 243) Men, it seems, can afford to be more frivolous in love. Other explanations (see Rubin et al., 1981) have emphasized women's presumed lesser emotional dependence on men, or have cited the greater stigma of spinsterhood as a reason for women's willingness to marry regardless of love (Knox & Sporakowski, 1968). Whether social changes increasing women's financial independence and making singlehood more acceptable will alter these sex difference remains to be seen. ^10