What should I think/do? He had me get a new credit card so we could 'improve my credit' but he's?

well you could make him pay it back or you could cancel the card is the card in your name or his if its in your name you could cancel the only other think if its in your name you could refer it over to idenity fraud but you probably couldn't do that if you gave him permission to use it also if he has a gambleing problem he might wanna get some help