This sounds very immature I know 🙈
My DP and his ex have two children together, haven't been together for 4+ years I met him not long after they separated.
They have always had a weird relationship in regards to their communication, it's not always conversations about the kids, sometimes I've came home and heard him on the phone to her talking about pathetic things like what car he's wants to get or how his job/her family is getting on etc..
Recently, her and her partner have split up, they've had the same length relationship as me and my dp but not so stable, breaking up every other month, and her partner is really insecure about her talking to my DP. I'm not really insecure but I do find the irrelevant conversations annoying.
Through friends of friends I found out some gossip about her ex's friend, very high school childish gossip but obviously shared it with my DP as I do everything: had a phone call today to say it has got back to said friend as my DP told his ex, she told her partner that I told her (lies because her partner tells her it's weird that they speak so much) etc etc etc
AIBU to think it's weird to still be gossiping with your ex when both have long term partners to do such things with!?
Sorry, very childish I know