IMO Quath is right on the mark! When you are dealing with and expecting the openness a polyamorous relationship requires, each person really has to internalize what he or she is comfortable and healthy in.
It's easy to get caught up in the moment but if the foundation of caring is not there you can expect challenges to get the better of you. When two different natures meet the foundations had better be made of marble!
Unfortunately I think Quath is right in your boyfriend not being honest, probably due to a failure to put himself in the headspace required to analyse the relationship or simply thinking he would find something else all for himself later.
If people were completely upfront in what they needed more and more people would form the type of relationships they are truly seeking I think. There would certainly be a little less pain during the search.
Take care, hope you are doing "not good", but "great!"