Op, if his finances are none of your business, then the rest of his life can be "none of your business" too. I know it is hard and you might be sad, but he is literally contributing nothing to your life, he is using you and costing you money.
End the marriage and officially separate, and start a divorce when you can afford to. It is good that you don't have any home or other assets. He is taking you for a complete mug at the moment and will continue to do so until you stop it.
If he has a key, then change the locks. If you think he might get aggressive then inform the police so it's on record. If you want to tell him face to face, then have somebody with you.
He is clearly getting money from somewhere and choosing not to share it with you. He is either on benefits and lying about it, or doing something illegal. He is using you to wash his clothes and house him and feed him a few nights a week.
Please put yourself first, end it, and move on with your life.
Keep posting here for support.