Drag his butt to rehab first. Not a cosy dotox at home....residential. Get in touch with a rehab centre and they might help you get him in there with some expert assistance.
And then when he is clean and sober decide if divorce is an option......especially if he is a cheat. Or if he is Gay...get a divorce.....have a honest chat or see some marriage counsellor. If he is just Bi. It might be OK but if he is a cheat or you think he is going to cheat.....chuck him like hot potatoes....but after a good chat/therapy when he is not not loaded.