So when dating throughout my 20s, I've noticed a pattern that is pretty common in straight relationships that almost always happens and ends the same way. I've travelled a fair bit and have many friends from different cultures, this pattern appears to be the same regardless of age, location and culture.

Stage 1: Initial attraction & courtship 1-6 months

A guy/girl meet and there is either minor or immediate attraction. The guy puts in a great deal of effort in 'wooing' her, getting to know her, her interests, her friends, her likes and dislikes, her plans and dreams for the future. They become closer, at first as friends but then slowly with more flirting, as more than friends. Eventually the guy confesses feelings and they become a couple.

Stage 2: Honeymoon phase 1-12 months

During the honeymoon phase, everything is rosy. He texts her 'good morning' checks in with her throughout the day, excitedly makes plans for the future with her. Dates are frequent and sex is extremely passionate and loving. The guy makes every effort possible to be a good partner, if she talks he listens, if she's sad, he comforts her, if she wants something for their future, he enthusiastically talks about how they can get it together. He is kind, generous, loving and attentive and naturally she is the same to him.

Stage 3: Devalue & Discard Months-Years

The good morning texts have slowly dissolved from every day to not at all. She calls him, he doesn't answer. He no longer plans dates, trips out or their future, all of this is now left on her. When she asks about the future, she's met with vague 'let's see what happens' or is brushed off. The cuddles, intimacy have all but gone, if they kiss it's once a week when they have sex (which is more akin to him using her body to masturbate). She increasingly does more and more in the relationship, working, cooking, cleaning, organising and paying bills, household maintenance, planning for the future etc and he doesn't notice or care. He regularly leaves their place a mess and doesn't clean up, if she brings this up with him, he ignores her or calls her a nag.

She doesn't understand what happened to the guy she met in the beginning, she put more and more effort into the relationship, starts reading about love languages, tries to surprise him with sexy lingerie, buys him thoughtful gifts, asks if there are any issues in the relationship, but she is ignored.

Months or sometimes years go by, she is now lucky to get a card on her birthday (with the price sticker still left on)

She has totally lost interest in intimacy, he doesn't hug her, kiss her, engage in any kind of foreplay, he barely even looks at her if they have sex.

At this point, she feels lonely, depressed, unattractive, unloved. She starts to wonder if it's her, did he stop loving her? Did she stop being attractive? Is it something to do with him?

Any communication is met with stonewalling, if she brings up any issue, it's blamed on her or blamed on something vague with no offer put forth on how to fix it (stress, jobs, etc) She tells him how unhappy she is and that she might leave the relationship if things don't improve.

She asks if he would go to therapy, he refuses.

She starts to slowly detach, spending less time with him and more time with friends, going out more alone, getting new hobbies, applying for jobs and not consulting him on how this would fit in with their future together, he doesn't notice or care.

Stage 4: Break up

At this point the woman has completely lost hope that the guy in stage 1 and 2 is coming back. She's accepted that he either never existed or is gone.

She breaks up with the guy and begins to completely sever her life from his.

This triggers an immediate and extreme response in the guy who will claim he 'never saw this coming' or 'didn't realise how unhappy she was' he will made immediate offers to 'change' and 'go to therapy' not realising the time for those things has passed and the feelings have now gone.

The woman will be slandered as a 'typical western woman who left her man' despite her trying for months or years to make it work. The man will often play the 'I offered to change and go to therapy but she left me anyway' leaving out the crucial timeline of him refusing to do anything and practically ignoring her for months or years.

I've often seen cases where the guy is with a woman but is obsessed with his ex who he see's as the one who got away. If the ex offered to get back with him, he'd immediately dump the new woman for her.

Almost every single relationship I have ever seen has followed this exact pattern, every relationship I have personally been in bar one has followed this exact pattern

What is the cause of this? Are men driven by the 'chase' but when it's over immediately discard the woman? Does this explain why relationships don't seem to last or seem miserable if they do?