Nate and I talked. He'd like to meet a female that he has stuff in common with, that he'd like to spend time with outside of sex, that he can have sex with. Like a real honest to goodness friend with benefits that isn't going to get clingy, like they value their independence and wouldn't push for more. He said Cassie had been perfect and he wished she could have made an effort to stay with us. She was a friend we both used to fool around with, who later moved in, in a platonic way.
He wants me to be friends with the person he's with, but it seems to me that I don't like the women he's with, so it makes sense for me to never have anything to do with them. I told him I'm not meeting anyone he's with, there is no reason for it. I don't make him associate with Sam, I should not have to deal with any of his women. I think that is the best way to keep thing drama-free.
He uses condoms. (I'd be okay if it was a long-term relationship for him to go barrier-free, provided they were clean and not having other barrier-free partners.) He doesn't bring anyone to our home and goes Dutch on dates, as we can't afford to treat. I think those are reasonable boundaries. If he honors that, and the fact that I won't be involved in his relationship, all will be good.