To be honest I really do not recall a time when I wasn’t sharing R. To put it into perspective we met in high school band in ’98. Much like other kids our age we were a raging ball of hormones and the experimentation of youth. Even before R and I had officially started dating I knew she was “fooling around” with her best friend during sleep overs. I was OK with it because we were also fooling around a bit after school as well and she would tell me about it. We always had an understanding that there is (for us) a separation of physical attraction and intimate romantic feelings. When they both combine it is amazing but for us they can be equally enjoyed.
So when we did realize we also had deep romantic interest in each other we didn’t see a reason that had to be mutually exclusive with her girl time sleepovers as long as she continued to tell me about it and that she promised to tell me if she was getting more romantically involved than physically involved. I even found that it was almost as erotic for me knowing that they were probably nude in bed together at that very moment while I few houses down was playing playstation in a heightened state of arousal.