I’ve sort of been here and really you need to be honest with yourself and just say ‘I’m doing this out of spite’.
I too really don’t get on with my in laws, they’re pushy, over bearing, opinionated and generally very rude to people. If they suggest one thing, I’m inclined to say something else just because I don’t like agreeing with them. Yes I’m being petty but they aren’t supportive parents and they have really upset us over the years.
Having said that they were never pushy about names (they didn’t mention the baby my whole pregnancy either). In my family first names can be anything both parents choose together (incidentally my DD has an Irish name spelt in an English way and you’d probably die but that’s another story!) however through the years second names have ended up being passed around. My sister (as oldest) shares my mother’s middle name, which happens to be my Nana’s formal first name, my Niece has my middle name, my nephew’s middle name (and my soon to be DS) share my Grandfather’s first name (Dad’s father), it wasn’t really planned, it just happened naturally as they’re nice names. It’s just a sentiment to honour someone we love.
When my DD was born I wanted to give her my Nana’s informal name as a middle name. Sadly whilst pregnant, my husband’s gran died and as I had chosen first and second name (he really liked and agreed to both thankfully!) I felt obliged to give her his grans name too, because what happens if we only had one girl? I agreed to a second middle name. Luckily his gran had a really pretty first name so our DD has three names I love. Plus the more names you have, the more unique it becomes.
A massive part of me wanted to be awkward and kick up a fuss about me being the one who’s gone through a 9 month marathon and she has his surname so why does he get a middle name too. But being realistic I would have been petty, it was just a middle name and I’ve never actually said it outloud for 4 years.
All these random things about culture, heritage, politics, money, they’re just excuses because you don’t like his parents but don’t take it out on your DH, he really likes his name and would like to carry it on. It’s a common and inoffensive name. In the grand scheme of things, I think he’ll really appreciate the gesture.
Good Luck with your baby, becoming a parent is wonderful and so much more than a middle name, pick your battles in life