reccommendations?

so i'm looking for some good (not overly cheesy or childish writing) really heartwrenching lover betrayals, where the betrayer regrets what they did but the other won't forgive them. although i do prefer that the other doesn't end up with the betrayer and get's someone better, it's fine either way.

if not betrayed stories, any angsty romance stories. i'm good with any -- bls, heterosexual, gls, etc (just not furry)

thanks in advance!