It kinda depends on the reader. But you mostly do forgive/forget since its such a common occurrence in yaoi :/
I mean its based on what kind of "bad thing" the character did,
but just imagine reading a "romance book" where the main dude starts off being abusive as hell, then suddenly he has some sort of epiphany and the next thing you know, he's the good guy and the other guy he was abusing is all in love with him.
Like what the actual fuck is that... that's straight-up toxic garbage.
But maybe if he just starts of being a jerk verbally(?) Or neglect/ignore the other person because of maybe his past or trauma then it kinda can be justified (but not always).
In manga, typically Yaoi. Sometimes you get a pairing in which the scene does something terrible to the uke. But then they sort of make up for it? And they have a nice relationship afterwards. Are we as the reader meant to be okay with that? Because the couple is happy, but we just read them being not happy. Are we meant to forgive and forget?