I am in the same boat as you, I crave my own space so much. Having a separate bedroom where I can hide out helps. I never wanted to live with a romantic partner and only have tolerance for very specific kinds of roommates. Living alone is a fantasy for me.

Living together after marriage (versus dating) is different, but our money has always been more or less combined from the start so it's not that. It's mostly circumstantial since I now work a job in which our schedules are synced so the alone time I am used to is gone. Pair that with no longer having a weekday off to run errands (fuck going to the post office/cleaners/car wash/shops on a weekend!) I feel like I am going insane.

It doesn't help that he would spend every moment with me if I allowed for that. I used to really enjoy having time off together but now that all of my time off is the same as his, I find myself coming up with more excuses to leave the house.

I think if you find someone who appreciates the same amount of space and alone time as you do, with the same expectations of cleanliness and budget, it's possible to cohabitate in peace. However, most people aren't into being in a LTR where you are mostly independent entities in the same home, not to mention that it comes with roommate-like annoyances when they have guests when you just want to be alone,so it's not quite the same as actually living alone.

I would ideally have two homes next to my partner and sleep in the same bed (almost) every night. He isn't going for that, and I don't blame him. Most people won't.

He is open to my moving out "for awhile" so I can get some independence back, but I know damn well that it will take a huge personality adjustment for the both of us for me to want to live together again. So, it's clear that once I am out of the house, our marriage is as good as done. So, I stay. He stays. We are both still trying to figure out what is right for us individually.

I, too, feel like I'm destined to either be alone forever (or rather, have a string of short term romances), or to stifle a huge part of my personality. I haven't figured out which, yet, but we are working on that.

TL;DR Don't move in with someone unless you are ready to end things if you don't like living with someone. Most people wouldn't stay if you moved in and then out. Can't say I blame em