Unsure of what to do?
I believe that if you truely believe from a place of self awareness that allowing him to move in (and vice versa) is what you want then should do that. But whatever your decision you cant have any doubts, because when something worrying comes up I think you will constantly revert back to the fight or flight mentality. Its a huge decision but you do have the answer. you are responsible for you and he is responsible for himself, so if you believe its not the right time then just keep doing what you're doing as long as you're happy and things will fall into place when they're ready and not forced or rushed.
Your reasoning makes perfect sense, particularly after everything you have been through. The advice I gave (of him to move in) was based on the fact that sometimes you have to put something under pressure to see if it will work. While ever you are living separately you can simply go away whenever the other person gets on your nerves rather than have to deal with the situation. Which isn’t sustainable long term. That being said, I understand your need for a peaceful existence and your desire to guard that protectively. Perhaps you could consider living separately but having the other person stay over for a period of time while you work on your relationship without putting too much pressure on it. That way you can practice your communication and work on your relationship without too much pressure? These are just all ideas to consider, and are not intended to force you into one thing or another, I just don’t want to see you in the same spot in 5 years time, not really committing but not really moving forward either.