Can desire and lust generated by attraction to a fetish create long standing emotional connections?

Or could it simply "scratch an itch" in one's desire for a kink regardless of the partner?

I have read accounts of one partner finding they loose the other when they change who they are or how they look. Specifically one women told an account where throughout her live she was overweight and her boyfriend of six years had openly told her one of the reasons he was so attracted to her was his fetish for well rounded women.

Well, as the story goes over a series of months she started a diet and exercise program and lost over 60 lbs. As she lost the weight her confidence improved as well and she started to go out to group activities more.

This change eventually resulted in her boyfriend leaving her. His primary complaint, she wasn't attractive to him anymore.

Surely the boyfriend was a shallow, narcisistic asshole only interested in his fetish desires and most likely had no true love for her as a whole person. But rather as a source of objective desire.

What do you think?
Do you have similar stores?

Let's discuss.