I can't say I don't understand him. He never truly got his chance with her. It's hard to just give up on that, having felt that way for so long. Maybe it's right, maybe it's wrong. You can't know for sure until you try.
Honestly, I think Picao only did this to please the reader, this chapter doesn't really fit in the impression from the previous two. Always think that the girl will and should stay as his bitter 1st love and he will move on with another girl.
Well, that's pretty much why you don't marry someone just for show.
It's nice to see a continuation to this series though, especially after what happened the first time around. Definitely a great ending and one they both really deserve.