Most Helpful Guy
Because you're selfish, you didn't want to be with him and now you see he's happy with someone else. You want him to be miserable which is not the case so you're mad/jealous
Most Helpful Girl
First of all that doesn't make you a bad person... Our emotions and feeling don't make us bad it's how we react to them.
I think you're better off focusing on how boring he was lol.
But for the record I think at some level you still like the idea of him...
Maybe you need to focus more on what you're looking for in a partner and pursue that :)