On a slightly different angle, I hope you are protecting yourself against the fall-out from his behaviour. I'm thinking sexually transmitted diseases and also your financial welfare.
Is your AH taking from your joint bank or credit accounts for these jaunts? His behaviour may escalate very quickly past a certain point and you could get dragged into the mess.
He may incur debts.
May be involved in drugged driving, and leave himself and you open to a crippling lawsuit.
He could have a secret life on the wrong side of the law which will eventually involve you.
Have a think about how you can quarantine your finances, insurance and legal status if he does something disastrous.