I think you are being used, moreover him saying it’s none of your business when he speaks to his family is particularly nasty, he should at least discuss it in general terms.
I’m in the opposite situation, my new partner moved in at my place, she gets an allowance as well as working 3 days. I value her companionship so some might say she has a good deal and she’s happy
You don’t sound happy with your partner, if he were to find his own place it would probably cost him £500 a month in rent alone, perhaps you should have a chat about that.