So, as to the title question, if a man is bisexual or heteroflexible, that's fine--monogamy is monogamy, and if he's with me, he's with me, not with anyone else. As to the other questions, a MMF is on my bucket list, but if it doesn't happen, so be it.
Want to spend some time wallowing in a Recommended Read? Pick one! Or two! Or seven!
It is an absolute turn-on for me! I think my favorite position would be one inside me and the other inside him. So many combinations, but I think that one would be the one I'd like us to do for the first time.
"Imagination will often carry us to worlds that never were, but without it we go nowhere.”
― Carl Sagan
Your question ist rather vague in the manner you've stated it...Isn't it?
Ask the Girls >> "Ist bisexuality in men erotic for you?"...may have been a better question if you're actually asking how we feel about it.
Erotic - Arousing or satisfying sexual desire.
Yes, I find it an erotic thing that bisexual men seem satisfied with their choices of arousal und sexual desire or they would practice it.
But does their sexual choice arouse me? NO
I'm BI und I'm not judging of a guy choosing a BI lifestyle either.
I once dated a foreign bi-guy, we had much fun even though we only went out that one time...But if I had chosen a guy to marry instead of Siri?
He would have definitely been straight. I wouldn't mind sharing him with other women no problem, but not with other men.
Which will most probably never happen, Siri ist perfect for me, she und I click in everything.
3some sex? I much like having two guys sexing me up, but no it doesn't tingle my twat to watch two guys sexing each other.