>>279958252You know, the drama 'Year of the Chameleon' does this, and it's somewhat notorious for the rather misanthropic ending.
The protagonist becomes a (relatively) successful businessman, and his cheating girlfriend hooks up with a high-powered exec, but the guy is such a chad that he's physically abusive.
Their last meeting has the protagonist look her in the eye (noticing that she has bruises) and say "You were made for each other, I'm sure you're very happy together." before walking away.
Interestingly, the protagonist never gets another love interest, he's kind of an evil shit at the end too.