This has been known to me for several years as she's been open to it about me from the beginning. My girlfriend is into the idea of seeing me with other women and also joining in. The first time I became aware of this is when she expressed her interest in a threesome with me. When she first told me my mind went instantly to a mmf type of threesome, having done one in the past had made me assume that was what she was referring too, but instead she was interested in a ffm. Long story short, she ended up inviting one of her friends over and we ended up having a wonderful threesome experience with amazing chemistry all around. It a thrilling experience for all involved, especially the age we all were when we did it being 18-19 in range. I noticed my girlfriend had gotten wetter then usual whenever I was with her friend when I had gotten done with her and went over to my girlfriend, she was practically dripping down the bedside. It was a surprise in every sense of the word. We used to do this sort of thing a lot more back when, when we had time though we have done a few things every now and again when we're off our jobs that I might share sometime here.