I think I've got it:
Men love slutty women but you prefer women who are choosy.
You do not prefer slutty women.
Ergo you are not a man.
That does upend my assumptions about you.
That was pretty much where I ended up at too.
Perhaps this will make it easier:
1) Women who are sexually satisfied are happier and more fun to be around.
2) Women have a much greater capacity for sex than men. So a woman who is your primary partner sleeping with another man isn't going to get in the way of your ability to have sex with her or connect with her emotionally. The reverse is not necessarily true.
3) Men in this lifestyle prefer women with healthy boundaries, who have figured out what they want from life and who don't consent to things they really don't want to do. I'd say it's a crucial skill to master for any woman in this lifestyle or it'll lead to endless drama, conflict and sometimes accusations of sexual assault.
4) A person having more than one partner doesn't mean they will sleep with just anybody.
I do find it strange how you didn't manage to figure it out on your own. All the information could be found in the two messages you were comparing. Were you unable to do it because you were trying hard to misunderstand? That's what it looks like to me.
But in case you where genuinely baffled; there's a classic on open relationships called "The Ethical Slut". It's an easy read. I highly recommend it. The focus in the book is lesbian open relationships, but for whatever reason, it's advice seems to be universally applicable to all humans, and is the most recommended and shared book on open relationships on the market. I'd say it's an awesome book on relationships for anybody, regardless if you are in an open relationship or not. The main selling point of open relationships is rejection. You will get a lot of practice in being rejected, which will give you a lot of information on why you were rejected. Nobody in an open relationship is going to settle for a lover because of a lack of options. Since people who have been in the scene for a long time have had a lot of opportunity to figure out in which situations they get rejected they get better at building healthy and strong emotional connections with those that don't reject them. They become very good and communicating. People who are shit at communicating in this world will spend a lot of time on their own. Hopefully, thinking on why they are alone. And because they will get so much practice on this, they will figure out why they keep getting rejected, can work on this, and won't be alone so much for long. Even people in monogamous relationships benefit from good communication.
The advice in The Ethical Slut for how to build emotional connection between people in any relationship is extremely good. Sexual or otherwise. Since you struggled so much to figure out the above logic puzzle I suspect you will find the book most enlightening.