If he is an addict, please be aware that you cannot reason with addicts. His behavior is not about you. dbmod is correct. You need to speak with a professional to get some help and support for yourself and some educated guidance as to how to proceed.
If you "out" him to friends and relatives you just make it more humiliating for him, create more anxiety for him, and make it harder for him to deal with this. Also, your friends are not qualified to make any judgments or give any advice about this sitch.
He may be sick. Do you remember your vows? In sickness or in health?
