This sounds terribly trivial but it's symptomatic of something which to me is deeply hurtful. My ex and new partner's ex, though we both met as singles and divorced, have a pool of mutual friends who are also friends of our exes (mostly his).
A few have continued contact with us both. But if they meet up with the ex wife, there are loads of happy group photos on their FB pages. If they see us, there are none ( I presume, in case they are tagged and the ex wife sees). I feel they have prioritised her feelings over ours. It's not just the fact that our so called friendship is invisible, it's the publicity that they give to the relationship with the ex wife. I feel let down and betrayed. I don't have an issue with mutual friends seeing us both but placing so little value on our relationship is hurtful. We invited them to our wedding and I'm really regretting it, knowing in advance they will post no pictures.