Me and DP weren’t married, but I’ll use the term MIL as it’s easier than ‘partner’s Mum’.
MIL is the type that’s obsessed with social media. Posts several times a day on Facebook and instagram about every aspect of her life. Posts if she’s ill, tired, annoyed, cleaned the house house today, went out somewhere, visited someone. She has lots of fall outs with friends and family if they don’t ‘like’ one of her posts or photos, and the only thing she ever talks about when we visit her is what other family members have posted recently and who has or hasn’t ‘liked’ it.
I’m the complete opposite. I use social media to stay connected to people, but I don’t post on it too often. I don’t post any photos of my DS, as I’ve heard about all the possible dangers and I also have a very violent and obsessive ex who used to stalk me via Facebook for years after we separated, but I the point that I had to make everything completely private and remove all mutual friends.
MIL knows all this, and we’ve asked her several times not to post any photos of DS to social media. For the first year she completely ignored us and I felt too uncomfortable to make a big deal out of it, but when DS was 13 months old I snapped and very firmly but politely asked her to stop it whenever she whipped her phone out to take photos of him. She sulked for months and started sneakily taking photos from waist height so we wouldn’t notice, but obviously we’d see them on her Facebook later that day. On his 2nd birthday she asked if she could buy DS a cake as his present, which I thought was really sweet. On the day MIL brought the cake and said she wanted to video him blowing the candles out so that she could post it for the rest of her family to see. We reminded her that there was to be no photos or videos for social media, we would take plenty ourselves and she was free to see them whenever she wanted. She grabbed the cake and stormed out of the house. DP lost his temper and phoned her angrily, and she came back and dumped the cake on our doorstep.
We haven’t seen her since, DS is now nearly 6. We’ve done everything we can to get her to see him, but she says there’s no point if she can’t post it to SM for her family and friends to see.
I don’t think that I’m unreasonable at all here and tbh I think she’s a little batshit, but DS is starting to ask why he doesn’t have any grandparents and it seems like such a trivial issue to deprive him of that relationship over.
YABU - Give in to MIL and let her post him all over Facebook so that they can have a relationship
YANBU - She’s in the wrong, she should want to see her only DGC even if she can’t post about it on Facebook.