So here's a weird thing. I'd be interested to know how you'd react in the same situation.
My OH and I have a mutual female friend of the last 6 years or so who we've hung out with a handful of times (she doesn't live that near), including at each others homes. Only each time in the last 3 times we've met up, she's run up to my OH & thrown her arms around him to say hello, proper OTT pleased to see him - but then completely blanks me. I'm literally standing right there smiling with my DD ready to say hello when she's finished with my OH. No "hello", not even a smile in my direction. Weird right? I've always said a friendly 'hello' first, but often don't get anything back, certainly no more than a quick acknowledging glance in my direction. The first time I thought nothing of it, by the 2nd time I thought it was rude, and the 3rd time I'm just downright confused and wondering if I should say something. it's possible she was like it earlier times we've met too, but I didn't notice then as there were multiple people to greet/lots going on.
So, Im pretty sure I've done nothing to offend her. We've spent time in the past talking about various things as friends do, even in between the initial blanking episodes when we first meet up, so I just find it a bit confusing. Especially since my OH & I have collectively have put in effort to be a friend to her. I'm pretty easy to get on with and don't have this issue with any of our other friends, or even friends of my OH who don't know me very well. So why the huge difference between how she reacts to us? It's almost comical at how extreme a contrast it is. Even my OH has said it's weird, and that I should ask her what's up if it bothers me. But I'm at the point now where I'm thinking, can I even be arsed?
I should add that about 2 years ago she broke up with her OH (a former mutual friend) after he cheated on her, so OH and I sided with her, sacked off the ex to be supportive to her the times we met up since the break-up. I should also add, without being descriptive or mean about her appearance, that in no way do I see her as a threat to my own relationship, and I'm not picking up those vibes (OH says not either). So what's the deal?