Apologizing to an ex? Is it necessary?

Apologize for what? People want different things from a relationship. If you were not getting what you want, then it's better to just break it off. You feel bad for breaking it off and that's why you want to apologize. He is hurt so he makes it about the gifts and the going out. But neither of you owes the other anything. You tried. It didn't work. That's life.