Guys, how would you feel if your gf wanted to have a threesome with you and another guy?

I’d tell her “what’s the guys name?” And gather more intel.

Then once I knew enough to keep tabs, I’d tell her “No thank you. I’d prefer not to do any 3somes. I like my relationships committed. If you insist on 3somes, put your money where your mouth is and do a FFM 3some with 2 girls first. Chances are, that idea offends you, soooo, you know how I feel about MMF 3somes too.”

That would be fine with me