Gambles to pay bills

My Boyfriend has a unsettling hobby. He likes to go to the casino and play at Craps table. When he wins, bills get paid, we get a little fun. When he loses, he has to find other means to make up for the loss. He doesn't have any debt from the losses and I hate that he gambles but I don't have a valid reason for hating it. I worry about having a future with him but I can't address it because it's kinda putting the saddle before the horse. I have spoken to him about how I feel about his gambling and he has explained that it's his way of making income. But i still worry about his losses. He lost $1500 this week but last week He made $1616 any thoughts?