Hi surga22 ~
Welcome to the Swingers Board!
From the way your post is written, you don't sound excited about - or even interested in - having a MFM with your boyfriend and his best buddy. That right there is reason enough not to consider it.
Yes, husbands and boyfriends can enjoy seeing their woman having sex with other men, but that is usually something that they are comfortable with only after the relationship is long-standing, where love, respect, and trust have grown over time.
If you are considering the MFM only to please your boyfriend, or because you fear you'll lose him if you don't agree to his request, then I suggest you do not proceed.
My gut tells me this guy is only thinking of himself. He may get off on sharing his girlfriends with his buddies...kind of an ego trip for him. He may have a reputation for this behavior among his circle of close buddies.
If I were in your shoes, IF/WHEN I was ready to consider a MFM I'd tell my boyfriend this:
I'll think about a MFM, however, I'm not interested in your buddy. If I decide to have a MFM I would want to choose the other male, maybe someone I know well and have had sex with before. Of course, you'd get to meet him first to make sure you were comfortable with being in a MFM with him. We both need to be comfortable if we do this.
I'd say that to him for two reasons: 1) to test this guy out and 2) to let him know where I stand. If he balked at me having some say in what I DO WITH MY BODY then this guy isn't worth my time of day. I'd drop him.
I hope you come back to post and let us know more about you and your relationship with your boyfriend. Ask any further questions you'd like.
When the time comes that you feel good and ready to explore MFM sex, the Swingers Board is packed with good information and advice. Please take advantage of what it can offer you.
LM