How do I tell my (32F) girlfriend (36F) that I'm uncomfortable with her asking a colleague of mine if she's a lesbian?
My (32F) girlfriend (36F) has never met my colleagues, but she has seen some pictures of me with them. We have created a fun group and sometimes go out to drink after work, and one of them in particular is this girl who dresses and presents herself in kind of a masc way. As far as I'm aware, she's only ever spoken with us about going out with men, and either way I don't put much interest in trying to figure out if she's hetero, gay or bi or whatever she wants to be.
My gf on the other hand comments every time she sees a picture of her how it's impossible that she likes men and that her gaydar is working. To clarify, I'm 100% positive there's no interest towards her on my gf's part - there might be some potential fear that this colleague of mine could possibly want to hit on me, though, even if there were never any signs on her part towards me so it's just her lingering anxiety of losing me speaking.
My gf has stated more than once that if she meets her she's going to jokingly ask my colleague if she's a lesbian. I am not at all comfortable with the idea of her asking, first because it's a question I would never ask someone, secondly because as much as we are friendly, she's still my colleague and I don't want any potential awkwardness on my job.
When I tried to tell her that the idea of her asking this was making me uncomfortable, my gf replied that it feels like I'm ashamed of her and her ways, and that she doesn't like that I'm so "protective" of my colleagues.
How can I explain my discomfort without making her feel rejected?
"It's none of your business."
"That's not appropriate."
"It's unattractive how obsessed with this you are."
"It's getting ridiculous and frustrating how you refuse to comprehend how inappropriate it is to ask someone that, even jokingly."
"I'm tired of talking about how un-funny this line of harassment is."
"It's odd how much you care about this."
"I cannot repeat enough how exhausting this is."
"That's not an okay thing to say."
"That's not how you should treat other people."
Rinse and repeat as necessary. Continue not to give into this being fun or funny. Blandly point out how rude and inappropriate it is until she drops it. If she continues to find it fun to push these lines...consider what that says about her character and if you really want to be in a relationship with someone like that. If she feels rejected, that's on her to deal with. It is not your job to manage every little emotion she has, and it's especially not your job to stop her from experiencing the consequences of her own damn choices. Stop holding her damn hand. She is a 36 year old woman. She quite understands that gaydar is judgemental, stereotypical bullshit and that someone else's sexuality is none of her business, especially someone she doesn't even fucking know. That's not cute, and she absolutely does not need the training wheels you are trying to offer her.