Ask a Bougie Chick: I didn't get married for this!

We're on day two of Ask a Bougie Chick week. I know we just discussed open relationships but here's an interesting conundrum. Today we have a gent that I'll call AB06 writing in over a discussion with his wife that is distressing him...
Hello OneChele,
I am sending you this email after reading your post about "Open Relationships".  I am a married man (6 years).  My wife and I dated for 3.5 years before we got married. We are both college graduates with Post graduate Degrees, professionals, mid 30's (38).  If you have a few minutes, I want to share my story, but also get your thoughts.  Right now, I am completely lost.
We started out as friends, dating exclusively, having a love connection and waited 5 months before we got intimate with each other. I stressed this because I knew once we got intimate, our relationship would move to the next level. Underneath our personalities, we are both were very sexual, she felt she was probably more experimental and adventurous than me (LOL), but we would talk about sex and our past experiences, etc. 
Fast forward to now, after being married and having 2 kids, the topic of Open Relationships was discussed one night while we were up watching the "Monique" Show. This prompted her to start doing research. My wife wanted to get my view/thoughts of having that kind of relationship. My initial reaction was "No", I didn't get married to you to be with other people, why is this coming up now, etc. My wife's response to me was she felt I was not being "sensual" enough with her and that although she feels I am good sexually with her, I may not be enough for her. She said maybe if I had another relationship with a woman, that I could learn something and possibly enhance our relationship. At this point was still in shock and still "No". She said "If I ever cheated" it wasn't a deal breaker for her, because of our foundation in our relationship. Which is why she thought an open relationship might work. 
Her position is that no species or human being on earth can be monogamous.  People have connections with people everyday (not sexual, but could be), so why block that human connection / experience.  I felt her for a sec, but I told her, Men and Women see people periodically and think in their mind a connection, vibe, or sexual thought, but doesn't mean people should act on it if they are in a relationship. If I was single, it would be different, but I am not.   
The topic ended there, but I brought it up again after 2 weeks of thinking about it. During this period, I was not only dealing with this but also the passing of my mother. With all of this, I just broke down one night on my own about everything.  My thinking was that I couldn't believe my wife brought this up as a topic in to our marriage. We have 2 little kids (3 and 1).  I told her at this point, that I am not interested in having an "Open Relationship." She stated that was fine, but she wants to discuss this more in the future.  I told her that if it's something she really wants to pursue, than we will need to discuss a "Divorce". 
She was shocked and got very emotional, because she later explained that she didn't see anything wrong with it. Her past relationships while she was dating except 1, were all open relationships (I didn't know this and she never put things in these terms when we were dating and talking about our past experiences.  My past relationships as I explained to her were monogamous.  So I concluded here is the root to this problem.)  
I have heard her rationale and I could see how people have these types of relationships.  But in my mind, I just think it's not right and could potentially involve too many feelings and emotions.  Thoughts?  
This is terrible but my first thought is that she wants to "stir cocoa" with someone else and wants permission to do it. Maybe there is some out of the box thing she wants to do sexually but if that's the case she needs to teach you how to do it before seeking that thrill elsewhere. 

I was having a similar discussion with some people the other day (both married and single) and one thing we all agreed about is that if one person changes the structural dynamic of a marriage without complete buy in from the spouse - it's a slippery downhill slope from there. If you don't want to share, that should be that. 

I'm also giving her a little bit of a side-eye for just now disclosing that she prefers open relationships. I think she didn't tell you earlier because she knew you wouldn't go for it and she wanted the ring. Now two kids in, she thought she'd put it out there and see what you had to say. I would suggest some counseling. Just because she said she's going to back burner the discussion, doesn't mean she won't act on it. I don't know your wife but if you were troubled enough to write in, you have your doubts. Have someone help you talk it through. The sooner the better.

BougieLand, what do you think? What would you do in AB06's place? Have you ever been in a relationship when someone completely changed the rules on you? Thoughts, comments, insights?