Weird friendship situation

[Secondguess]

I'm looking for advice/ thoughts from anyone who's been in the middle of a weird friendship triangle.

We're all middle-aged, although it may not seem so.

Basically a couple of years ago I became really good friends with someone who has another, main long-term friend (LTF) . Apparently LTF feels insecure about our mutual friend being friends with other people, and at the moment, specifically me.

I'm in the middle feeling like an affair partner over middle-aged friendships where mutual friend would ideally not mention to LTF that she's been out with me etc or she feels guilty when talking about mutual friend and I spending time together.

Stuff that for a game of soldiers. Unfortunately though mutual friend is someone I really enjoy spending time with, but I feel like walking away.

LTF (who I don't know) apparently has bad anxiety and depression. Mutual friend is not very assertive / ignoring the situation.

Had anyone else been in a similar situation? Wwyd?

But if you dont see Long term friend how does it affect you? She doesnt have to mention you to her and you can enjoy mutual friends company without her. I wouldnt walk away from someyou you like spending time with. Good friends are like gold dust as you get older.

Fair question - I feel uncomfortable now because I realise that by suggesting meeting up with Mutual Friend, her response isn't the usual "that sounds great" / "that doesn't suit", it's about whether her LTF is free/busy/might want to see her that day. It seems like mutual friend feels awkward about agreeing to meet up in case LTF has the day off and wants to see her, then I feel awkward about the whole situation.

I don't have a single group of friends, I have different friends from different times in my life and talk to each of them about spending time with the others. "did you have a nice weekend?" "yes I saw Jane and we did..." sort of thing. With Mutual Friend and her Longterm Friend, it feels different although they both have other friends too. Possibly also a bit codependent with the mental health issues/ support.

Tbh, OP, it sounds from your second post that your friend is doing that awful thing of not agreeing to see you in case she essentially gets a better offer from her other friend.
Does your friend always have this response when you try to arrange plans? Do you actually spend time with your friend?

I don’t think you’re feelings are unreasonable at all.

Personally I would find it energy draining and wouldn’t put up with invariably having to be the second option.

@olivehaters said good friends are like gold dust when you’re older, but the irony is that in this case, she really is NOT being a good friend to you.

On the contrary, I’ve learned that time is far too precious to cling onto friendships that simply don’t work for whatever reason. In my case it’s usually been down to one-sidedness.