Sassy,
You say that you have only "dipped a toe" into BDSM. There is a phenomenon called a "sub frenzy", usually happens to new people. It is a manic time where your mind runs from one fantasy to another, each one more extreme than the last. Your mind runs about a gazillion miles an hour, like, "ohmygodthisissofreakinggreatiwantmoreiwanttodoeve rythingrightfreakingnow!"
Even in subfrenzy, baby steps are a good way to go about it. Maybe look into your local scene and see if you can find a mentor for Hubby, who can help him to be more strict. It is unrealistic to expect him to go from zero to 60, in one session. Men have some programming to overcome (don't hit girls, treat your wife with respect, etc).
Look very carefully at your fantasies. Are they realistic? BDSM is, in some ways, no different than nilla. We still get caught up in the rose colored glasses world of perfect Doms who somehow know exactly what we need, perfect subs who revel in absolutely anything that their Dom wants to do and have no limits, and where "real life" never has the gall to intrude its ugly head.
Frankly, there are lots of fantasies that should stay fantasies. (i have several of that variety, doesn't stop us from verbally exploring them, but we both have sufficient sense to know taking them real time would be dangerous to me, to him and/or to our relationship).
And to add to the earlier posts about communication. Let me empahsize that part of communication is listening. He is telling you something very important about himself. Monogamy is important to him. Is it a dealbreaker? You'll have to find that out.
Be careful, and make sure the ice will bear your weight before you go do the watusi in the middle of the lake.
rose