I have a really good friend who I met about 10 years ago when she was still with her husband. She and I had a shared hobby so she became part of a big friendship group very quickly and her husband was part of it too. Genuinely became good friends with both of them owing to generally just ‘clicking’ and several shared interests.
They split up 5 years ago rather acrimoniously. Most of our group took ‘his’ side but my DH and I were careful not to take sides and continue to maintain friendships with them both.
They are both now in new relationships, happy and seem to have moved on which is great for them both.
It’s my 40th birthday and I’m having a party and will invite both of them (plus their partners). Should I give them both a heads up that the other couple are also invited or is it unnecessary?
I have no problem if one or the other would rather not attend etc. - I just don’t want to blindside either of them.
I’d give them a heads up. Not on the invitation itself but via a text message or phone call. You don’t say whether they have seen each other recently, but if they haven’t, it could be awkward for everyone if it comes as a shock to see each other there.
My best friend got to be friendly with my now-ex while we were together. DH and I, and ex were all invited to her wedding, but she sat us at opposite ends of the room for the reception and warned each of us that the other was there. We weren't acrimonious but a bit awkward.
Let them know, and don't force them into each other's company. But it should be fine.