Respecting a relationship

Trying not to rant, but I’ve been dealing with some issues at work that just don’t make sense to me. I work with my girlfriend and it just seems like other women working there our age find it playful and appropriate to flirt with her or make jokes about us like calling both of us their girlfriends or saying “oh we’re a throuple”. One has even gone as far as to say her boyfriend is jealous of my gf and thinks she’s made his gf (our coworker) bi-curious. It’s just so constant and my gf laughs it off as a harmless joke and everyone says it’s just like work culture like having a work husband or wife. Idk, I doubt straight girls enjoy their bfs being hit on, it just all seems so rude. I feel like if it was a straight relationship it wouldn’t even happen, or at the very least, others wouldn’t laugh it off when brought up.