Neurochemical reasons why a woman should not sleep with a man until after he has fallen in love with her, and how to train your brain to fall out of love (hint: block and delete scientifically works!)

Love is like a drug addiction

Brain imaging via fMRIs show that a brain in the initial stage of love looks like a brain experiencing a drug addiction. The scans compared people's brains when looking at photos of the person they said they were in love with versus photos of random people. When people looked at the one they love, they had more activity in the VTA and caudate nucleus. These release the neurotransmitter dopamine, which are linked to feelings of pleasure.

Heightened activity in the VTA has been associated with addiction to nicotine, alcohol, heroin, gambling, etc. with each dose causing a fresh spike of dopamine. This is why people say they are "addicted to a person." The brains of those who have been rejected in love looked like addicts going through withdrawal.

Romantic love is more of a motivation that changes behavior than an emotion. It is an important drive of human behavior, with a drive defined as a neural state that energizes and directs behavior to obtain a biological need. In contrast to mere sex drive, which does not focus a person's efforts to a single mate, romantic love evolved among mammals to promote a directed, longer-term attachment that would lead two mates to remain together long enough to raise their offspring.

In women, oxytocin tends to continue to be released after sex, whereas the same is not true of men. Therefore, unless his feelings were already strong and powerful before sex, they will not grow after sex, whereas her feelings will grow each time after sex. Semen can also have effects on a woman's psyche. In animal studies, seminal fluid "makes the female’s interest in other males plummet."

Love is "blind"

When people are in love, they have reduced activity in the prefrontal cortex and the amygdala, brain regions that are involved in decision-making and making critical assessments. The effect is a willingness to take more risks, even ones that would normally seem reckless while in another state of mind. The reduced amygdala activity makes people in love less prone to making negative judgements about the one they love.

People in love have higher levels of cortisol, which causes feelings of stress and anxiety. They also have lower levels of serotonin, as low as those who have obsessive-compulsive disorder, which can lead to obsessive and intrusive thoughts about the object of love.

The biggest difference between the brains of males and females that is not related to hormone binding sites is serotonin: the rate of serotonin synthesis is 52% greater in males than in females. Women's serotonin levels begin lower, so when they fall in love, they do not become nearly as obsessive as men. The lower serotonin level is perhaps the reason why many men have issues such as stalking, jealousy, and controlling behavior.

Losing first love is worse for men

Men are terrified of being in love with a woman who does not love them in return. Men project their sexual imprinting to women and believe that the first man to take a woman's "virginity" imprints her to him for life, when the truth of the matter is that most women's first experiences were terrible, and they likely did not come close to having an orgasm or imprinting. Men are projecting when they want to know women's sexual history, because they are much more likely to be hung up on their first love.

Some guys, decent guys, deal with the loss of love by staying single and working on themselves. However, many guys just keep dating and keep using women, and never put their heart into the relationship. They often think they will get back with a past love, whom they hold up on an idealized pedestal. Be very careful about vetting guys' emotional past, in addition to their sexual past. A guy who isn't truly over his past love will never be able to fully love another woman. All the "lost love" has to do is say hi to him, and even if it is decades later, he will be tempted to throw away his entire life, if he thinks there's a chance with her.

There are some high profile examples of a man going single-mindedly after his first love, such as Jason Momoa, who said of his wife Lisa Bonet, “Ever since I was like, 8 years old and I saw her on the TV, I was like, ‘Mommy, I want that one. […] I’m going to stalk you for the rest of my life and I’m going to get you.’"

He didn't care that she was over 10 years older than him, and the fact that she was married previously to and had a child with Lenny Kravitz didn't bother him either. It is also clear that a man does not need to have sex with a woman to know that he loves her and wants her.

"I didn’t tell her that until we had two babies, otherwise, I’d be creepy and weird. But yeah, just always wanted to meet her. She was a queen, always."

Love can last, and long-term attachment looks a lot like parental love

A 2011 study of couples who have been happily married an average of 21 years found that, when they looked at photos of each other, brain activity was elevated in the VTA (just like in new lovers), but also the ventral pallidum, an area associated with maternal attachment in animal studies. Over time, more oxytocin and vasopressin are released. These are the same chemicals that bond parents and their children, and these neurochemicals increase feelings of affection, intimacy, and commitment.

The passion is still there, but the stress is gone. Cortisol and serotonin levels return to normal. Love, which began as a stressor to the brains and bodies, becomes a buffer against stress. Brain areas associated with reward and pleasure are still activated as loving relationships proceed, but in a healthy, long-term, loving relationship, the constant craving and apprehension go away.

You can train your brain to fall out of love, just like you can recover after an addiction

According to scientists, you can’t make yourself forget, but when you start thinking about someone you want to forget, you can redirect your brain. In her research, Helen Fisher observed that when subjects in the fMRI machine shifted their focus to an unrelated task, the hypothalamus calmed down and stopped producing the dopamine that was making them feel lovestruck.

The key is to train your brain to something else that requires your concentration, something that takes a lot of brainpower. Also, remove photos, voicemails, anything that reminds you of them. It is important to stay away from the person to get over them, like when quitting smoking. Don’t call, don’t write, and don’t try to be friends. Block and no contact should be the default response.

Through putting people who’ve been rejected or dumped into the fMRI machines, scientists can see that the attachment reduces with time, just like brains can heal from past drug addiction.

By understanding the neurochemistry of love, you can take better control of your emotions.