We held DD 4th birthday (outdoor garden) party yesterday. There is an ongoing feud with my brother and his DP atm but my DD is still very close to their 4 year old son (her cousin). They see each other 2-3x a week at their Granny's.
I text my brother and his partner 3 times inviting and then following up to see if they were coming to the party. No response, so in the end (perhaps too aggressively, in hindsight) I text to say there was no need to come, they really should've let us know one way or the other by now (they have no regard or courtesy for anyone), and in fact I was rather insulted that one or other of them didn't bring their son over to see DD on her actual day of birthday (in contrast, I drove there (50 mins each way) with a 3 month old baby in the back of the car so that I made sure the cousins saw each other on the day of his birthday).
Anyway, clearly my DM doesn't approve. I could tell at the party she was annoyed I'd effectively cut strings with them. I'm always the one pleasing everyone but this time I decided to cut the chord with brother as I'm always the mug making the peace with everyone.
Mum (who is very active in DD life, usually she would be in the thick of it with the kids) did nothing but stand at the end of the garden and bitch with my aunt. Clearly it was about this whole saga. She had a face like thunder, didn't get involved in any of the festivities. She looked awkward when she cracked a smile. I didn't hear exactly what was said, but they didn't realise when I was stood approx 6 feet behind them and could hear mine, my brother's and the kids' names used with a disapproving tone. This must've gone on for close to 90 minutes. Sure she helped to clean up and she offered a couple of the guests a drink but otherwise she just stood there bitching throughout. My husband who is usually oblivious to any kind of politics or drama even mentioned mum looked like she was in a terrible mood.
I'm so cross because if that's how she felt then she just shouldn't have come. I want to say something along the lines of "next time if you want to just stand and bitch about us whilst in OUR home then I suggest you don't come". AIBU to say anything? Should I just leave it? Would you be pissed off? Advice please.