Redpepper, Polynerdist (her husband) and I have had threesomes where she is the focus as I am straight. I found them to be bonding between me and PN and certainly took away the idea that having sex with his wife was wrong. I enjoyed them although I didn't feel a great deal of energy like I do one on one. It's like my connection was held back and I wasn't exchanging energy like we do when we are alone. They were fun and definitely positive experiences for me.
Group sex in general with other couples or people around me doing it is not something I gravitate towards. I don't like the sexual energy of people I am not intimate touching me nor do I want them to share in mine,. Oddly enough I can watch strangers have sex, like porn, and become aroused, but the idea of watching people I know have sex disturbs me. There are very few people I want to know in that way. Plus I don't like seeing friends naked....what can I say, I'm not very sex positive I guess