There are three choices for a person in your situation: 1: stay and be happy, 2: stay and be unhappy; and 3: leave.
You see some redeeming features: he's nice to you; he's great with the kids, he's a good helper. Maybe you need to just accept that this is the best it gets with him and try to be happy.
My main concern though would be that addiction is progressive. It gets worse. And he doesn't seem to show any sign of wanting to stop.
But really, the ball is in your court. He is showing you who you is. He is not interested in changing. It's up to you to accept it or not.