Boyfriend questions threesome!?

Ella

My boyfriend and I are both 16 years old almost 17, and have had sex about 13 times in the past 8 months. Lately the past two times we had sex, afterwards he questioned "which one of your friends would you think you'd have a threesome with?" I am not gay or bi in any way so honestly I don't see myself having a threesome with any of my friends.. also I would never want anyone else to pleasure my boyfriend like I do. He never brought up any names but for some reason he's interested in having a threesome and if I'd ever date a girl because he'd be turned on my that... is this something I should try or just tell him I am NOT gay 😅