He does it all the time. He seems to think he is the expert on everything. Can't back it up with evidence/sources either. He just 'knows'
E.g. we are in the process of selling our house. I mentioned that we can't take bolted on shelves. He is adamant that we can, despite never having done any research. He will then get angry with me and then eventually look it up. After which I've 'misunderstood' him. I'm sick and tired of this. Once in a while I wont back down and we'll have a big argument where I accuse him of gaslighting. He will eventually apologise and promise to never do it again. We have had this exact same argument hundreds of times.
What happened today takes the biscuit. We disagreed over the area equaling 10 square meters. He got angry with me and then looked it up. Which showed him I was right. Apparently I misunderstood him. Thing is, I have a maths degree, he doesn't... so why on earth did he try to argue in the first place.
AIBU of being sick of his mansplaining?