It seems to me that you've already made the decision.  Acting on it may be just as tough, or worse.  But don't waste your time on a relationship that's doomed to fail.  Letting it slide to avoid the pain of breaking up is a mistake.  At least, it would cost you time, possibly a lot of time.  We have less of that than we realize when young.  I don't know anything about your situation here, so I can't say much more.