In my experience in the BDSM and kink communities, it is not uncommon for heterosexual men to be happy to connect with bisexual women though they don’t want any other men around. Many non-monogamous men have this one penis policy as well. They want to be the only person with a penis in their relationships. They find bisexual women exciting because they think that this means they might get to indulge in two of the most common male fantasies: Watching two women getting hot and sexual together and having a threesome with two women.
It’s the fantasy that most men bring up as soon as they find out I am bisexual. Question 1 is usually ‘Do you have a bisexual girlfriend?’. Question 2 is ‘Will you bring her to bed with us?’. If the answer to 1 or 2 is no, the next question is still ‘Can I watch?’ or ‘Will you tell me about what you do together?’ They never consider how inappropriate questions of this sort are.
I took a look to see if there was any science to explain why this might be and I was not able to find any research. There is plenty of research that places the fantasy of sex with two women together ranking in the top fantasies of men. But nothing about what they find so exciting. So I decided to do a bit of research of my own. So far, this is only an informal poll but I may do a more scientific survey soon.