Yes, it indeed is a big red flag.
You mentioned "Here's a hint: Is his reaction towards you different in relation to his male sponsorees than these female ones? "
Yes, his reaction is absolutely different. He does not have a problem having me around when he meets with his male sponsees. He has started to lie about the phone calls as well - telling me it is someone else rather than the truth - female sponsee.
I wish I could do something and have someone else approach him but I have no contacts with his group members or his sponsor. I guess in time, these women will learn a very hard lesson.
He is putting 110% into these relationships and on the surface he seems like the perfect caring guy - willing to listen, willing to be there for comfort day or night. Isn't that what we all want? But I know the truth will surface in time and lessons will be learned - the good part is that I will not be around to see the results.
Thank you for confirming my beliefs and making me stand taller and stronger.