Adult child

I have a 20 year old son who is living in an apartment with a roommate he didn’t choose, and he hates it. I instigated him moving out because he was playing way too much Xbox and not following basic house rules – and I gave him lots of notice to get on board or he could govern himself in his own place. It’s been almost a year since he moved out, and honestly life has been SO much easier since he left. But every time I see him he makes comments referring to how I kicked him out and how stressed out he is financially. And it looks like he’s planning on moving in with his girlfriend in August (at this point he doesn’t believe in God or religion); it could be good for him on some level to choose who he lives with for once. I don’t feel like inviting him to move back into the house is the right move for a number of reasons, but it’s also hard to connect with him especially when it’s clear he’s blaming me instead of enjoying being independent. What can I do to shift our relationship into a more positive space, and do you have any specific situational advice for me?