She sounds like my mother. I am truly sorry, OP. Look into getting a restraining order against her.

I feel like I'm possibly missing some information here. Either way, I feel this also speaks of you not setting boundaries. You need to have a sit down conversation and tell mom that you are an adult, who can make decisions, who will include her as you so choose OR if already done so (or unable), I think it's time to cut her out of your life. A partnership is between the two people and will always fail with outside influence.

There is a distinct possibility that Mom is doing this on purpose so she won’t be alone. Ultimately the only practical solution is to get your own place and move out. And never, ever, under any circumstances let her “borrow” a key to your place.

sounds like it might be time to cut ties if she's not respecting boundaries... sorry you're dealing with this :/ also would just like to recommend DBT therapy if you're able. Best of luck!

That's terrible. I'm just too distracted by your use of the word "fella." Are you from the 1940s? I'd think a fiancé would get a better title than "fella."

You gotta lose her if you can. Shes doing this on purpose and would hate to see you happy. If it’s your third or fourth partner to do this, how many of them have been vocal and tried to communicate to you that your mother is nuts? And did you listen to them or just brush them off and excuse your mom for them? Like others said, theres gotta be something missing

the fact she is like this is not your fault. the fact you have allowed it to continue to this degree, IS your fault. don't tell your mother shit. if she comes over unannounced, don't open the door. if she calls excessively, don't answer. this is only happening because you are letting it happen. woman up and set boundaries and stick to them. if she breaks a boundary she gets a time out

Gosh, this sounds like my mother in law. Super nosey, and always trying to ruin my day