If I take my escort hat off, and write purely as a woman, my question is thus: what are the women getting out of being in this closed circle relationship? If it were me, would I just go about my normal day, go to my day job, etc, and just accept that 50% of the time, my ‘boyfriend’ will sleep with me, and 50% of the time he will sleep with someone else? Who gets his non-bed affection such as conversation, cuddles, etc? Women want the non-sex bits of a relationship as well, and is the OP going to be around/able to provide that to two women at once?
Also, is the OP suggesting that these women live together? Fun fact: when women live together, their menstrual cycles sync so that they ovulate and have their periods around the same time. Which essentially means that you may only get sex for 3 weeks out of 4 anyway.
There just doesn’t seem to be a lot in this relationship for the female partners unless they are being provided with a place to live, or are allowed to sleep with others (polygamy), which the OP has suggested is not the case.
When I first read the post, my first thought is that the OP wants unprotected sex with both parties, hence the closing of the circle.
@roots reggae is correct- money could be the only answer. With which, I put my escort hat back on.