Most Helpful Guy
Sounds like a choice between the psycho situation which is a pretty solid bad one vs. a situation that is really uncertain. When you move in with someone you really get to know a lot about them, mainly all the pissy sh*t they do that annoys you and the equally pissy sh*t you do that annoys them. Just a natural characteristic of 2 people living together.
Seems like you and this new boyfriend are hitting it off rather well so it may be best to hold off to keep the early relationship fire burning hot. I'd opt for plan C which would be to ultimately focus on finding some other living situation. In the meantime it might be best (and safest) to move in with your new boyfriend under the pretense of getting the psycho off your back until you can find something else to go on.
Under this pretense you would be free to move out if you and your new boyfriend don't jive together super well. You can easily explain to him that you would prefer not to go reeling headfirst into a heavily committed situation after your most recent relationship, and he will understand where you are coming from. He should be able to accept you wanting to be tentative about the whole thing.
If you do happen to get along really well while constantly up in each others grill's, then perhaps you got something really good going on and your boyfriend would be happy to have you stay and so would you. The whole thing sounds like a tricky situation so keeping your options open can be a good overall bet.