I don?t know how to manage SIL. She is a very strong force and it?s her way or not at all and I find her really difficult. She asks questions and then ignores anything I say, repeating her point. She watches a lot of daytime TV, which I don?t because I work, so don?t really know what she?s talking about, but when I say I haven?t seen something she?ll argue that I must have and is very put out if I don?t just agree.
Recently we were there because she had asked us to drop MIL round to hers, we agreed but told her we couldn?t stay as we had plans. Obviously she ignored us because when we arrived she then got annoyed that we weren?t staying for dinner. 
Since then when we?ve seen her she makes sniping comments about how we always get arrangements wrong and how our indecisiveness costs her money. This is one example but there?s loads more.
The rest of the family indulge her but I find it maddening. We see her every couple of weeks and it always the same ? sniping comments sometimes referring to events going back years. She?s worse when she?s at our house. Most of it is aimed at DH, although sometimes she turns on me. I?m usually very confident but I just don?t know how to handle her as I don?t want to cause a massive row but don?t want to feel I?m being put down or watch DH be put down in public.