Most Helpful Girl
Just because he was the one to break up with you, doesn't mean he cannot be sad about the end of a relationship.
He most likely re-evaluated the whole time you have been together and decided that it would be for the best to part ways. Breaking up is hard, especially if you have been together for quite some time. Even if there is resentment and contempt there, he still had feelings for you because of all the time you spent together.
Doesn't mean he wants to work on things, but his sadness is not unfounded.2