“3some”with roommates & GF apparently meant “cuckold” [MMF]

Recently, my gf, one of my roommates and I had a 3some (live in house w/ bunch of other students from our college). my gf, him, and I were hanging out drinking the other night. My gf just (somewhat unexpectedly asked him if he wanted to. It was pretty awkward silence for a few seconds but he was down lol.

Well, this is my first 3some, and it was NOT how I expected ehich was that we’d both take part.. somewhat equally. Instead, he nearly shoved me over when I tried to join in. He’s almost bodybuilder level muscular and ima beta, so I wasn’t about to try and argue with him. He had us take a sec for a brief discussion, and said that he’s only ever the dominant one in a 3some and that he’s not interested otherwise, gave us a safe word to use and asked if we had anything else to add/any limit.