Please do not tell your H anymore about your finances. You already know that he wants out because he told you he did. If there was anything more to his coming around and spending time with you and his son that was his chance. He's got a vested interest in wanting this to stay as amicable as possible. You said yourself that legally you can't divorce, so why not play his cards right and hopefully you'll pay down some of the debt and he comes out the winner.
If I had it to do all over again I would have taken my extra money and put it away instead of giving it to a man who was playing me and stringing me along.
