I don't think there is anything anyone could have done to make me to quit. Maybe my wife leaving with the kids, but that wouldn't have made me quit long term. It wasn't until I had had enough where I quit for good.
I would talk to him and explain why you are concerned. Not sure if an ultimatum is a good idea, but I would stress that this isn't something you will live with. The thing with that is you would have to follow through if he doesn't quit.
Imo, you need to decide what is best for you. You can't control him or his actions. You can't make him quit or love him enough that he'll quit.