Let me just say this:
I fucking HATE all the negative hype around the "It's not you, it's me" routine.
Of course it's the fucking "ME" in the situation; why would it be "YOU"? If a man breaks up with a woman because she starts talking about kids after one year, it's not because she started talking about kids after one year; it's because he's fucking spooked that she's talking about kids after one year. And there's nothing wrong with that. My advice: use the damn "It's not you, it's me" routine, because it's the fucking truth.
Furthermore, this is why the "You deserve someone better routine" is a joke as well; because when someone uses that, he or she is implying that the other person is their primary concern. That is never the case; if it were, then the person instigating the break-up would make an effort to change, since he or she cares so much about the person.
In that situation, say "It's not you, it's me; and the truth is, I want to sleep with other people."
I can't stand how people knock the "It's not you, it's me" routine, and in the same breath knock the "You deserve someone better" routine; they're the same damn thing.
/rant