I am divorced and I have a large house. A friend of mine went through a divorce about two years ago. He lost his house in the divorce and he had nowhere to live, so I have allowed him to live with me for the last two years. He pays half my mortgage payments and utilities etc, so it all works out. Also, my house is large enough that we both have some degree of privacy and we don't feel we intrude on each other that much.
We both have girlfriends and they can go to his side of the house and we don't really get in their way and vice versa. When we are alone in the house we think nothing of walking from the bedroom to the kitchen naked, for example. We aren't shy around each other at all. One time we even sat in the living room naked after showers and watched TV. It was during that episode, watching TV, talking, and so on, we talked about sex with our girlfriends and before we knew it we both became hard. It was more humerous to us than sexy. We were joking about it.
Gradually, we both started slowly jacking ourselves and before long we were diligently jacking off. We had no desire to jack each other off or anything like that. We just enjoyed the openness of jacking together.
Ever since then, at least once a week, we will sit together on the couch or in a couple of chairs and jack off together. It's just a social thing we do together, like having a smoke together or having a drink together if that makes any sense. We have discussed attempting to get our girlfriends into a masturbation session with us, but we don't know how to bring the subject up. We think it would be fun to do it together in front of them and hopefully get them to do it too. I don't know if that will ever happen.
We do enjoy our almost weekly jacking routine together ... and we are far from being gay or bi!