Ugh. I wrote a huge reply and when I hit "send", got a login screen instead!
So I'm just going to rehash my take on everything quickly.
1) Lack of communication - not your fault, not his fault. See this as a learning experience to communicate in more detail, more explicitly, before next time (if there is a next time)
2) I think your husband is hurt and scared, so he is pulling back. It's too early to tell whether he is "truly" mono, or whether he is just trying to protect himself. I think blaming him on his reaction, or blaming you, is not a constructive way to view the situation. (as an aside, boundaries change, obstacles come up, feelings can get hurt, etc. expect this sort of thing with poly & open relationships. The "cure" is usually lots of respect, trust, love, and communication)
3) Poly forums everywhere all seem to have at least one view in common: ULTIMATUMS ARE BAD. But instead of simply condemning the act, view this as a signal flag that there is some work to be done or some issues that need to be resolved. It's unlikely that he's issuing an ultimatum because he's a controlling jerk. It's more likely that he is attempting to control the relationship because he feels threatened, hurt, and scared. Try to get at those issues so communication can be restored.
(as an aside, obviously he is not handling the situation in the best manner possible. But both of you are new at this, and mistakes and mis-steps are bound to be made, so at this point, I think taking a tack of empathy and consideration regarding his attempt to control the situation is the wiser course)
4) I personally think that most healthy relationships do have "off limits" behaviors, but I'm not sure this is the majority view in the poly community. My view is that if two people are in a loving, committed relationship with the other, that they DON'T WANT to see the other person hurt. That doesn't mean don't talk about anything. That doesn't mean things can't change. But I think maybe giving him the time for both of you to work through this without the (what he now sees as a) threat of another relationship will be the healthier way to go, and the quicker route to rebuilding trust. It's entirely possible his viewpoint will change when he's in a good place again, but it may not. Again, it's too early to tell. I would personally suggest holding off on attempting to re-open the relationship until that point is reached.
5) It's OK to feel bad that your husband's feelings got hurt. But unless there was some intentional deceit, don't think that you're a bad person or untrustworthy. I think these types of situations happen pretty frequently in poly, especially if the couple is new. Navigate these situations *as a couple*. I heard some excellent advice on another forum: what's good for the couple may not necessarily be what's good for Person A or Person B. I've found that to be true in my own (brief) experience with poly. (caveat: this isn't intended as a recipe for simple self-sacrifice - that's not good for the couple either. It's been helpful for me to view my own relationship with my wife from a different perspective than two people both struggling to get what they want, in isolation and opposition to each other)
Last edited by hoorayjeebus; 09-04-2011 at 08:55 PM.