During an argument. It was mostly over the fact that she keeps meddling in things eg our new house, basic decisions that should be all mine but she keeps sidling up to him and whispering in his ear, ltelling him what her preferences are (carpets, kettles, etc etc) when I've already told her what I've chosen.
We argued a lot as I have a general issue with how she always does this (and how he actively seeks her opinion).
Him saying this is a big deal for me and I don't think I can see a way back from it. It's annoyed me to the extent I've put him in the spare room.
What would you do?