Sally,
What about gently confronting him? In a calm voice and a supportive demeanor, approach him and ask what his plans are for paying down this debt. I think avoiding the elephant in the room with you is not the wisest thing to do, considering that you are married and 50% of that debt is presumably yours. But I don't think that attacking him is going to work either. Maybe a calm and practical approach would help him face up to the mess he has made of his life.

What are you afraid will happen if you confront him?

Honey