Most Helpful Girl
If you want out of the relationship, that's a reason right there.
He doesn't need to lie/cheat on you/hurt you or do something else you don't approve of. If you don't feel the same anymore, and don't see yourself in the future with him, it's ok to break up. And generally, once you start feeling this way, you can hardly go back.
Besides, would you want someone being in a relationship with you and feeling this way about it? No. Break up may hurt your boyfriend right now, but in the long run, it's better for him as well.