What an entitled mother-****er! I would NOT be tolerating that! He does NOT get to choose to leave your marriage, yet still treat you as if you were his wife by staying over that often and 'keeping' you by supporting you in that way. He definitely wants his cake and be able to eat it too and no way should you stand for that. What happens when his bit of sex on the side gets sick of the arrangement? How will that affect you and your DD? You need to get legal advice now, and don't trust a single word he says to you - this will only work as long as it's working for HIM because afterall, you only found out about this because you confronted him on it.