I mentioned to MIL earlier in the week that I was going to do a family activity with my DD aged 2 on Saturday, and invited her to come. She said that she couldn't as she was babysitting DNephew on Sunday and was planning to run errands on Saturday. Fair enough.
Rang SIL (not the mother of DNE) this morning to ask if DNiece would like to come along to activity with me and DD, and was told that MIL was taking DNE and DNI to an activity that was unsuitable for DD, (they're a little older than her, but the activity I wanted to do with her is suitable for all ages)
AIBU to be a little upset that my MIL is having all her grandchildren bar DD and taking them on a day out that she can definitely not do (too little) without mentioning to me or inviting along, when we could have had a day as a family all together?