I would never watch over any kid that accused me of anything or whose parent accused me of anything. It is really just asking for trouble. The courts usually side with bio-parents vs. others, such as step-parents. No way. Idiot kid did this just once! I told DH I would never watch her again. Of course, her BM had also done it 2 times. I never, ever, ever watched her again alone. If DH had to work, he couldn't see her until he got out of work. They later of course complained, but I stood my ground. No way I would allow someone to possibly accuse me of something. Best decision I ever made.

Next time she asks you should point this out - and then say NO-!!!!! from that point on :evil:

I have SDs aged 17 and 15, and when they were little, I would never babysit for them because BM was and is, a total psycho. I did not put it past her to make up abuse claims against me, so I made it a rule to never even be alone with them until they were teenagers. Even now, I prefer this not to be the case - because in any case I am disengaged and would not see it as part of my role.
I think this woman is taking extreme advantage of you by behaving this way - and I would urge you to stop doing favours for someone who treats you like shit and talks rubbish about you.

We teach people how to treat us.

I struggle with this situation sometimes too. BM does not have a single nice thing to say about me, but I'm perfectly fit to watch her kids when she wants to go out and party all night.

But I love those kids and I really enjoy spending time with them. I don't care if BM doesn't "like" me or has bad things to say about me. I have no direct interaction with her. She deludes herself into thinking that DH is really the one watching the girls even though she knows he's at work.

There is a lot of talk on here about disengaging and distancing yourself, but I can't see how that response would ever be good for me. Like it or not, these kids are a part of my life, even if it is only part time, and I just can't imagine disclaiming any responsibility or pretending like they don't exist. DH is also very supportive, and is very active in their lives, so I don't have the issue of all this responsibility falling to me and only me. I suppose I'm very lucky in that arena.

Also, they're relatively good kids compared to some of the stories I've read here. So who knows, maybe it will change over time. But for me, I don't care what BM says about me. She doesn't get the opportunity to say it to my face because I don't give her the chance. And she seems perfectly content talking sh*t about me behind my back to people I don't care about.