Has your husband dated at all since you began practicing poly? It seems that you're not open to the idea of him having a relationship because it would be a distraction from working on the marriage. Sometimes it is benificial to work on individuals first.
Hanks experiance with dating did help us all move past the insecurity and jealousy he was feeling about what Darla and I shared. It was a new perspective for all of us and in the end we are all better for it.
Me - bi female hinge of a closed V / developing triad
Hank - my husband of 15 years.
Darla - long distance girlfriend of 1 year.
We have seven dependent children between us.