I hope he does leave you alone @30somethingandsingle. The turning up outside your house thing is worryingly arrogant. Don’t feel bad about yourself though.
Years ago I started dating this guy (a friend of a friend). A few weeks in he started showing signs of being worryingly possessive and paranoid/jealous. We were out (with his best friend, who thankfully was a good guy) and he got really weird. He started imagining that his best friend and I were having an affair and being really difficult. The best friend made sure that I got in to a taxi without him and I resolved never to see the possessive arsehole again. (Not ghosting, as the situation in the club made it very clear that it was most definitely over - also he was a bit scary, so I didn’t think I owed him any contact).
Anyway, a few days later he turned up at my flat. Luckily it was a block with a secure entrance. I was in with my son and he kept phoning me and pressing my buzzer and telling me all sorts of bullshit about how he loved me 🙄 and I should just let him in. There was no way I was going to do that. I had to phone his best friend and get him to come round and take the scary weirdo home. I never heard from him again, thankfully.
It’s a good job that he was overtly a bit scary. If he’d been convincing and kind he might have talked me in to letting him in etc. After that I did end up in a 10 year relationship with an abusive arsehole who was much more convincing and properly good at mind fuckery.
With the scary guy, it was really obvious to me that staying with him would end up with me being totally isolated from everyone and almost certainly sporting bruises. With my horrible ex it was more like boiling a frog - very hard to see until I was very isolated and feeling that I was somehow to blame for his abuse).
I’d worry that your MrS would be much more like my horrible ex. Nightmares rarely come with the huge, flashing warning signs I got from the possessive boyfriend. Or, if they do, they’re able to convince you that they’re not warning signs at all.