If he asked you to move in with him, he is prepared to support you, which means a lot. If he doesn't ask you to chip in for living expense, no need to give him money, just buy food and grocery, and cook for him when you have time, or buy him cloths and other stuff he need. That way you show your gratitude without getting awkward.
Most of guys are willing to support their stay-in-home spouse, sp you don't need worry about it too much on share the cost of living.