How is that toxic though? If he decides he doesn't want Shauna to fuck him up the ass is that 'toxic'? If he doesn't want Bailey to choke him is that 'toxic'? Neither of those are 'fair' or 'equal' either, different partners in a relationship can want different things out of it and that's fine if they're all compatible. There is absolutely nothing wrong with him being fine with multiple girls but not wanting to share them, so long as they are fine with that arrangement too. If things started out with him being like 'I'm going to fuck other girls and if you don't like it you can leave' to Jamie then yeah, that would be toxic, but that isn't even close to what happened.
I mean, I really don't care less if there is an option for him to take that attitude, I just won't take it, but I hate the idea of portraying anyone who would prefer not to share the girls as a bad person. That's what I have a problem with.