One more thought real quick. You're right "allowing" or "denying" your partner various freedoms feels icky, like you're a parent not a partner. Thus the idea of operating under boundaries not rules.
Rule: No sleeping with people I've never met.
Boundary: I would not be comfortable knowing you were sleeping with people before I got the chance to meet them personally and get a feeling for them, because I wouldn't have any idea if I thought they were safe, cool, or trustworthy.
Rules have punishments ("no sex for a month!), breaking boundaries have consequences ("if you did that, I think I would probably feel disconnected from you and unsafe and would almost certainly need to pull away physically for a time, maybe emotionally as well").
Setting rules is a means of control, explaining your boundaries is a means of self-care and communication. It's largely a semantic difference, yes, but it does matter and can lead you to different places. You can flip that around easily and see how "you have permission to see her" becomes "it would be ok with me if you saw her".
Of course, this all depends on if you trust your husband to respect your needs if they're expressed as boundaries rather than rules...
The major players. Me, 30ish bi female. Gia, girlfriend of 4+ years. Clay, boyfriend/dom. Davis, ex/friend/"it's complicated." Eddie, roommate & fwb.
The supporting cast. Eric, Gia's husband. Bee, Gia and Eric's toddler. Dexter, Gia's lover. Helen, Eric's lover. Izzy and Nikki, Clay's partners. Liam, Eddie's husband.