My boyfriend is absolutely obsessed about doing it with me and another girl.
I told my girfriend and she wants to do it. I am jealous about the thought of her with
my boyfriend. She is very sexy and I know she likes him. I fear that I will be the odd one out.
Does anyone out there have any advice?

Don't do it if you have the slightest concern about your girlfriend or boyfriend. Threesomes are many guy's fantasy. They can be fun but in my experience they are all different and not predictable in how they actually happen. Whatever happens does tend to change the nature of how all three of you will always think of each other. If your girlfriend is interested in your boyfriend it definitely could create a bond between them that ultimately might bring them together and leave you out. For it to work out right your boyfriend must be very close to you and highly trustworthy and the other woman must respect your relationship with him and defer to you. You are best off to not do it with those two. If he is so insistent to try it and you are into the idea too, find another girl who is no threat to the two of you.

I have this fantasy as well but frankly I know so many who tried it and ended up breaking up. I know there are people out there who can "swing" without problems but usually it ends up creating problems.

They say the famous poison mushrooms taste terrific - I will have to forgo that experience as well.

In your situation,you should NOT consider a threesome with ANY women that you are aquainted with. The safest way ,is to hire an escort and after the it takes place, you never see the woman again. Also, do not allow any pictures to be taken and you choose the motel or room it takes place in. The positive aspects of an escort is you can choose a woman whom you and your boyfriend think is most beautiful and it will not come back to bother you because she is gone foreever. Most escorts are very beautiful and very clean and most have sex with either men or women.