I have two thoughts on this, if I were to give my husband and one of his girlfriends an anniversary present. My very first thought was that I would stick to a gift that gives them an experience, like dinner or concert tickets. I don't think I'd do a weekend getaway for them, but that's mostly due to cost.
With a physical gift, unless you are buying something that has two parts, one for him and one for her, it might be more frustrating than anything, trying to figure out where to keep it, whose house it stays at, etc.
Also, are you sure that they would be comfortable with you giving them a big, expensive gift, like a weekend getaway? I think I'd be uncomfortable if my metamore gave me and our shared sweetheart anything extravagant on our anniversary. I'd probably check with your wife, if I were you, to make sure everyone involved would be comfortable with what you'd like to do. Personally, I am not sure I'd feel comfortable with my husband giving me and my other partner anything for our anniversary and I know that my other partner would not be happy if my husband gave us an anniversary present, since he doesn't really like me giving him presents, but tolerates it since it makes me happy. Just something to consider.
I second the wine and a card idea, if you get anything at all. Personally I've only ever done gifts for other people's relationships for major milestones (like 25 years together, or something). It feels to me like making big gestures makes the anniversary a public event, when it's more of a private thing. Just my opinion mind!
Yeah, TheKnight bought a nice bottle of wine for AnotherArtist and I, and it was really sweet (not literally, I don't like sweet wine) but anything more than that would have been a little odd, I think.
Though that's a fairly compartmentalized relationship - if y'all are closer, like, hang out a lot together or live together maybe a bit more might be appropriate? Something acknowledging that the boyfriend has a role in your life too as a friend or whatnot?
Depends I suppose. Lady has sent some celebratory chocolate or cheese or adult beverage down with real when we celebrate our anniversary. I've taken their kiddos overnight to give them space to celebrate theirs without having to worry about a sitter.
But it's not an every year thing. Any large gift would weird.
Jaeger gave Tails and I a mindbogglingly obnoxious singing congratulations card the first time we slept together. Not sure if that counts or not The sentiment was appreciated, but the card was promptly put out of it's misery in a "freak" milk accident.
I would give Jaeger and Tails something for their anniversary, but I'm sleeping with both of them, so it's a bit different of a situation. I also seriously love giving gifts. Love it. So, any partners of mine have to be accepting of getting gifts for basically everything. I'm not such a big fan of getting gifts, myself, though. I am comfortable with my hypocracy lol
We don't generally celebrate anniversaries, but recently was MrS's and my 20th wedding anniversary. We didn't plan anything ourselves but Dude took us GoKart racing and made crab legs and lobster for dinner.