DP of six years has an old female friend. For context and in the interest of not drip feeding she was once his girlfriend (more than 25 years ago).
I get on well with her: we've met up along with her three kids and my kid a few times, the kids get on well and she and I have a good rapport and occasionally message one another. She lives a long way away so we hardly see her. There's no suspicion or jealousy on my part and I like her, but I have only known her a couple of years, I probably wouldn't choose to hang out with her if she wasn't DP's mate and she is very definitely "his" friend and not so much mine.
She got a nice Christmas present for my DD and for me and DP, rather unexpectedly. I said casually to DP when DD opened it that I was mildly embarrassed that I hadn't got her kids something and should we get something small for them? He messaged me today from work to say: "Have you got something for X,Y and Z?" I replied to say: "no, should I have done?" And he messaged back to say: "I've got an Xmas present for (the mum) so I think you could get something small for the kids."
DP is not usually one of those blokes who outsources life admin and family relations to his partner: he's very good at managing this himself and always remembers presents for his friends, doesn't make the assumption that this is my job etc. So I was a bit taken aback at this.
I am mildly peed off that he's more or less asked me to buy presents for his ex-girlfriend's kids. I wouldn't have minded if he'd made it a "we" thing: ie "shall we get a book token for them?". It was the way it was phrased as a "you need to get onto this" thing. Not sure if I'm over-reacting.