Well, I don't think that's exactly true. It depends on the girl.
Also, calling the MC "my man" — which at least
Lori, Julia, and now Cassandra have all done — isn't something FWB typically do. They call it for what it is: still the level of a friendship with some added fun. I'm not saying this couldn't end up in more sharing or that at least some of them won't end up being OK with being part of a harem, but I think using the term
friends with benefits to describe others besides Lori is probably a bit inaccurate. I
do think at least some of them are that way right now, though:
Daphne, Haley, Barbara, and Natasha all seem to be in that state, although I would also note that each of them is steadily and heavily becoming more addicted to the MC.
I don't just mean addicted to his stick, either. For example,
Natasha is willing to continue to sleep with the MC — without recordings, without Robert's presence (virtually or otherwise) — and that despite his warning that he would not only end their sexcapades but consider it cheating and divorce might likely follow. I think that means at least subconsciously her relationship has passed being just sex and friends. Otherwise, why risk it?
Barbs has already made several statements to show she really doesn't just think of the MC as a good lay. Sure, she's still careful
because she doesn't want potentially to ruin her relationship with Lori, but she seems to be in love with the MC, whether she's admitted it to herself or not.
All of this is just my opinion, but I would venture to say that, except in a few cases, relationships have now progressed well beyond just "friends with benefits". I am, of course, dating (or whatever you actually call it) all of them as well.