Dealing with Stalkers and Unsupportive Friends

I have a couple of stalkers — my ex and their current partner — that are really frightening. Not in what they’ve done, per se, but in what they’ve shown they’re capable of, and how my ex has fed my personal information to their current partner while we were still supposedly friends. Some of my current friends claim to support me, yet are still friendly with my ex and don’t discourage their presence. I know it’s supposedly toxic to expect your friends to cut off someone that you don’t like, but this feels different. I worry those friends are feeding my ex information about me, or that they aren’t as trustworthy as I thought. I’ve talked with my friends about my concerns before but nothing seems to change. I hate how paranoid this situation has made me feel, but I wonder if this is reasonable? Or am I just being too controlling?