Magick should not be used to meddle in other people's lives. Your ex boyfriend has to make his own choices in life. If it is not physically harming you or endangering you, then you should let things go on their natural course. Altering people's lives whenever you feel like it will have serious reprecussions! You need a very good reason, and it needs to be a personal one. If he asked you for help, it would be different.
He is an ex, which means you are now removed from him in that way. I think your best course of action is to work on your own emotions and mind frame (there are broken heart / letting go healing spells if you wish to go down the magickal route)