Hey Jess.. we were writing at the same time!!!
I am working on calling people on things, but my usual MO is to just stop talking to them. When I get upset enough to confront, I usually end up crying...
And I don;t want SIL to come over and hang out!! She ends up giving me WWAAYYY too much info about her social/sex life when she does...Plus, she is an odd, prickly person. I do know if someone treated her the way she treated me, she'd beat them up.. (she has been known to get into bar fights!!) However, now the babysitting is occasional, not nearly as much as it was before. It's not frequent enough to be a real issue,anymore. I think she knows when I am at my limit and backs off.