I don't know this would get to me, but it just does!
My DP's ExWife still has his surname, and they have kids. He divorced a while ago but we are not married. She does contact him a lot to get him to 'do stuff' like fix shelves, a bit less so now. She sends his in laws cards for their birthdays and Xmas always signed 'from the X surname family'.
Maybe I should just get over myself and not think about it. But it makes me feel like she is still in my DPs 'family unit' more than me. We will marry at some point but the thought of taking his surname also makes me feel weird, like I'd be wife number 2!
Anyone else feel annoyed? Or and I just getting wound up over nothing?