Have Never Seen Her yet

I am 26 now my two Beautiful girlfriend s are both 40+. We have been together for six years. From the beginning we have had stay Overnight and Stay Over the Weekend parties. They have sex with other women. They arrange what other women I can sleep with.So from our parties and they are pretty well know in the lesbian and Bi word in our area. And it's will known among there friend's that they occasionally will share me with there lady friends. A mature lady friend of there's had a request. She wanted to spend a night with me if it would be possible. I guess she a good friend of there's. I personally don't know who she is. Anyway her request was she wanted to spend a night with me and did not want me to know who she is . She gave them a hood to put on me before she gets to our home. So they had me undress put the hood on me and put me in the bed . She entered the room and I could hear her getting undressed. Then laying down beside me and started playing with me and making out with me. She got me hard and mounted me in the 69 position for quite a while. And she got off in my mouth a few times. Then she lays down on her back and pulled me on top of her and we fucked till she was out of wind. So we took a break after a while she started giving me a blowjob and got me hard again this time she wanted on top . Everything we did was just from her moving me around to were she wanted me she never spoke a word ever just sex sounds. After the first night.. she and my girlfriend's made arrangements that she could spend two nights a month with me it's been a little over a year now and I still don't know who she is. She only allowed my girlfriend tell me she is a white lady in her 50s . They also told me on a normal week in our town I probably see her a few times a week and a few times I have talked to her. Me and this lady have had hours of sex together and I don't have a clue who she is. With out being able to see it's made the sex very exciting. So I really don't need to know who she is as long as she is enjoying this beautiful thing. I know she more than likely has sex with my ladies also I will go along with it as long as she wants,