It's not you...it's me.
A popular line of ASSHOLES who initiate a breakup or a popular answer you get when you confront some SWINE who suddenly goes silent and gets lost without even expressing intentions of closure.
"It's not you, it's me."
Question: Why say that? Do you think it helps? Why not say on my face that you want to get rid of me? You play culprit but you effect the same thing => HURT.
Obviously, the purpose that line is to somehow "ease" the pain of the poor guy who still wants you; the guy who didn't understand why you left and who couldn't figure out what he did that made you scram. It is always said on the excuse that one has a "deeper problem" than what seems to be on the surface, something one has to resolve himself, or something he has to take care of which is FIRST in his line of priorities. It may be indecision or any other self-crisis. That is the facade the line usually creates.
Does it make a difference? Why not be man enough? Speak your truth. Say you have found somebody else. Say "I don't like you anymore, I have somebody better than you."