How to live with someone without getting overstimulated and have meltdowns/shutdowns?

So, I (27F) started dating someone (28M) a few months ago. We've known of each other for 10 years but only occasionally met through mutual friends. He's also autistic and has ADD.

Things are great. We have a lot in common and get along very well. The relationship feels healthy, we communicate and solve things that come up together, laugh and play a lot and so forth. It's still early, but I can see myself with him for a long time to come and he has told me he feels the same.

The thing is: I'm someone who needs a lot of alone time to recharge. Especially since a massive burnout I had a little over a year ago. If I don't get this time - (usually I need at least a day to recover after intensive social situations) - I have a very painful shutdown. And I need it to be time alone. Time without any pressure to cook, clean, speak etc. Time for uninterrupted hyperfocus and occasional naps.

My bf wants us to live together eventually. I'm not sure just yet. It's partly because his cleaning habits are a big concern for me (which is something he has shown me he is working on), but mostly because I'm not sure how I'd be able to balance living together with the amount of undisturbed alone time that I need to remain healthy and sane.

We just spent four days together at his place. The first two days were wonderful. However, at some point I noticed myself starting to slip. It was a very small cabin (combined living room + tiny bedroom with windows to the kitchen) and it was freezing outside so I couldn't spend much time out. I didn't realise until it was to late that I was becoming overstimulared and needed space. I just felt myself becoming tense, irritated and very tired. Eventually I said that I needed to go home and he immediately said he'd drive me. I tried to hold it together but ended up having a shutdown in the car (full on rolling into a ball, shaking, going non-verbal and blacking out). He remained calm, held my hand and told me he loved me, and proceeded to carry my bags up the stairs to my place, tucking me into bed and making me a snack. After a while I said I needed to be alone so he went home.

This was yesterday - on new year's eve. I'm sad that I wasn't able to spend it with him. We had planned to make a chicken steak and drink sparkling wine in the outdoor bubble bath while watching the fireworks. Instead, I spent the evening in bed with a book. I couldn't even get up to watch the fireworks alone. Didn't even have the energy to talk to him on the phone. This was our first new years together and I know he was excited for it. I was too.

My concern now is: how am I supposed to be able to live with him when I can't handle four days together without having a complete shutdown? We'd need a place large enough for me to have my own room, which I have a hard time seeing how we'd be able to afford. And even then, I don't know if that'd be enough. If I'd be able to get the recharge time I need, complete undisturbed alone time without responsibilities, with him in the same house.

How do you handle living with others/your partner? Any advice would be much appreciated.