I would say that I've been primarily heterosocial for a long time. I met two friends at college at approximately the same time. Much of the school assumed I was dating the female of those two, rather that they were dating eachother. Eventually they married. It was easy to stay friends with both of them.
I met R under in a different but very heterosocial group and we got involved (though with a well defined first date). R was clearly also heterosocial. We frequently spent time with the above mentioned friends. One night R was very tired and wanted them to leave so that she could go to bed. I suggested she just go as I had no problem spending time with my two old friends. To my surprise R displayed a strong discomfort with breaking the gender balance. She felt it was very important to be there to interact with the wife of the pair (despite her being better friends with the husband). Someone, my heterosexual gf had strong homosexual expectations but only in a small couple environment.
An anecdote
I met R under in a different but very heterosocial group and we got involved (though with a well defined first date). R was clearly also heterosocial. We frequently spent time with the above mentioned friends. One night R was very tired and wanted them to leave so that she could go to bed. I suggested she just go as I had no problem spending time with my two old friends. To my surprise R displayed a strong discomfort with breaking the gender balance. She felt it was very important to be there to interact with the wife of the pair (despite her being better friends with the husband). Someone, my heterosexual gf had strong homosexual expectations but only in a small couple environment.