NC as this is outing. Very long and probably confusing.
Some background:
DFIL and DStepMumIL had very little contact with DSMIL’s sister, they didn’t get along when children, so they just stayed out of each others lives which is fair enough.
DSMIL’s sister has been regretting not making much of an effort as she is now all over them(last year or so), they humour her but keep her at arms length obviously still making the effort at family events etc.
DH’s 2 brothers all think DSMIL’s sister is a bit of a twit, only met her twice however in the 10 or so years DFIL and DSMIL have been married.
Anyway, DSMIL’s sister and new man are getting married soonish, DH’s brothers and partners are going, and our Niece and Nephew are flower girl/page boy at the wedding. We had decided once we got the invite back in June that we wouldn’t go, as DH wasn’t particularly bothered, it’s 2h30 mins drive there and also we have just bought a new house, so we didn’t really think we would have the money for hotel/drinks. It is during the week too and me and DH don’t have a lot of holiday left at work, so after DFIL raising concern that he was a little upset we weren’t going, we did discuss again but came to the same agreement, declined invitation and left it at that.
Since then we have been to a small family gathering where it was spoken about, so DH and I did discuss again whether it was worth going on the way home from said family event, but again came to the same conclusions, a lot of miles, didn’t have the money for the hotel and it wasn’t worth it as we don’t actually know them that well! Little sad to be missing out on seeing the rest of the family, but it wasn’t worth it for us.
Anyway, last night DH went to DFIL's for dinner, I was working late so unfortunately couldn’t make it. He’s come home and told me that he is now going to the wedding on his own. DFIL told him that his mother could no longer make it as she was having issues with her hip and struggling with walking etc. so she didn’t think it was suitable. So there is now another space at the wedding, and did DH want to go now before he told DSMIL’s Sister that his mother could no longer go. DH said yes, actually he could take the time off work, and since I have the most fuel efficient car, he would drop me at work, get my DM to pick me up after work to go to hers, and he would pick me up late that night on his way home from the wedding. Apparently he did ask if there was another seat for me, but as only one person was cancelling we couldn’t both go.
AIBU to be absolutely fuming by this? We spoke 3 or 4 times privately about the fact it just didn’t work to go, and a couple of times with DFIL and DSDMIL and declined the invitation. He’s come home and doesn’t understand why I’m pretty upset, the fact that he is going on his own now, therefore he has completely defied anything we ever decide together if his DFIL can persuade him otherwise.