Lets play make-believe. Imagine, your in a relationship with a wonderful partner. They're loyal, appreciative, funny, intelligent; just an overall great person. Now after nearly four years of dating this person, they gradually change into a completely new person. They no longer care about you in general, and just mainly focus on themselves. The catch? They're aware that they're treating you like shit, they just can't help it. They claim that they're in a phase where the just can't care about you, yet they want you to sit idly by and just wait for this little phase to pass. A month later, and things have only only gotten worse. You've tried to establish some connection between the both of you multiple times, but they refuse to talk to you about their issues. Basically, they're downright refusing to make things better in the relationship. What do you do? Edit: Thanks for the responses guys, they helped more then you understand. Now I'll throw in a random variable. Let's say for whatever reason you had an affair about a year ago prior to this. You were attending a social gathering, where drinking (and quite a lot of it) was involved. You reacquainted with an old friend from high-school, and in a drunken frenzy engaged in intercourse. You we're honest with your partner and confessed your crimes, and somehow made things better again between the two of you. A single year has passed without a hitch, but how differently would this influence your actions?