Not wanky in the sense of trying to show off, but wanky nonetheless.
I hosted a celebration for our child's First Communion, which was postponed due to covid. Restrictions in place in church, very limited guests. So my family, who live 200+ miles away, didn't come.
I spent around £150 on food and catered for all XH's family (they live locally, so could easily just meet us at mine for a meal afterwards). About 15 of us in total. XH said he'd bring drinks. I only had one glass of wine as I didn't trust myself to be polite to him if I had more. He'd brought 6 bottles. A few people were driving, so not much was drunk and there were some left. I thought I'd have a glass after they all left.
XH took the spare bottles outside and hid them in a bush in my front garden. DC told me later that ex-FIL had paid for the wine, so it was even really XH's.
I happened to see him hide it when I went to the front room for something, and then I also saw him pick it out of the bush as he left, because I was in the doorway waving goodbye to everyone. He waited for all his family to go ahead of him, so none of them saw. So he knew it was a petty thing to do!
He also assisted his sister in packing up more than half the leftover desserts to take home when I asked if anyone wanted a slice of anything. So he was happy to take from me!
He was actually quite nice to me that day, and I thought perhaps he did appreciate the huge effort I'd gone to to cater for 15 people. He made a bit of a show of saying goodbye and even hugged me and thanked me for putting on a nice meal. As it was not 10 minutes since I'd seen him stash the wine in the bush, I said through gritted teeth "you could have left me a bottle of wine then".
Kind of hope the scenario rings a bell with ex-SIL (ex-BIL's wife) and she recognises this as XH. Pretty sure she's a Mumsnetter.