Boyfriend doesn't clean up. Help

Been with him over a year now. He lives in a flat on his own with 2 cats and wants me to move in with him. I said I will when I'm ready as it's a big step for me to live with someone. He understands and is patient with me. He's never been great at cleaning up. Just thought it was a man thing. Forgets to take the bins out and do the washing up. He's never asked me to clean up for him but it's something I do when I have time as he works long hours. Last week he had a bunch of bin bags and rubbish sitting in the front room. Said he would sort it the next day. I stay over last night and see this pile of rubbish is bigger and a collection of full bin bags by the front door. He hasn't worked all week so I know he has had time to clean up but hasn't. I thought I would help by cleaning up what I could while he had gone to work this morning. I've never seen it so bad. Must have been about 8 bin bags full and he had run out so was using shopping bags to fill his rubbish in. Dirty cat litter and mouldy food. The washing up he hadn't touched in the sink for over a week. No clean plates in sight. I feel physically sick and can't imagine myself living with him after seeing this is how bad it's got. I'm curious to know if he even thanks me when he sees how much I've cleaned up after him. What do I do?