I've been with my boyfriend 4 years, we are both approaching 50 with teenage kids.
He has been acrimoniously divorced for ten years. Although theyd been divorced several years, in the early stages his ex wife didn't know of me (he said she'd been difficult when he'd had girlfriends before). Then there was a period about 18 months where she knew of me, I was always polite and respectful (she was less so) and she would make things 'difficult' by for example making sure her ex had the kids on my days off (she knew my working pattern). She would also create a lot of drama (her relationships are usually volatile, so she'd be phoning her ex day or night angry because she'd broken up with her latest love or whatever).
At one point she became briefly friendly towards me and tried to sew seeds that my boyfriend wasn't to be trusted, he'd cheated on her in the past etc. I dealt with all politely and respectfully. Then after a while when i didnt heed her warnings and dump him she started calling me and leaving abusive messages etc (I've changed my number so this stopped).
Of course there will be a link between her and her ex/my boyfriend for several more years til kids are 18 (and possibly beyond if he keeps talking to her regularly beyond then).
I spend the 50% of the week that he doesn't have his kids with him and love him. We get on very well and he's very caring and good with my kids too.
However, since she became angry towards me, when I see his kids it is kept secret. I feel very sorry for them. He has told them not to tell her they spend any time with me. I know she also tries to sew seeds of doubt in his mind about me, that I'll leave him or whatever. She wants him single.
Her behaviour is very controlling. I know he is the only one who can address her behaviour.
What would you do in this situation?