My siter in law (husbands brothers wife) absolute hates me and will do anything to get one over on me and after what she has just done I dont think I ever be able to get over it. For years now she's done little passive aggressive things whenever im around like telling my husbands niece to call me 'harriet' rather than auntie like all his other 5 brother's girfriends/wives get called. Anyway I planned my mother in laws birthday recently inviting close family round for a get together with some buffet food and a nice cake, it was a surprise so Mother in law had no idea. The day of the get togther rolls around and no one turns up at the proposed time. So i ring around my other sister in laws... turns out the sister in law that hates me told all the family coming that we were having a surprise birthday meal instead at some fancy restaurant (everyone assumed i knew) so everybody was there and im sat at home with a huge buffet and a fancy cake and no one to eat it all. I honestly couldnt get over how she let me plan it all and buy everything (even suggesting certain foods to buy!!) knowing no one would turn up. My husband is fuming and as a result he has had a massive falling out with his brother, mother in law still doesnt know about my surprise get together because honestly im too embarrased to tell her whats gone on because im well aware of how childish it is, for gods sake we are all supposed to be adults and this sort of behaviour is happening. Im obviously going to have to see her at some point because we are related and my kids normally see their cousin once a week at least so will be questioning why they dont see her anymore. I just dont think i can get over this, has anyone got any advice or been in a similar situation?