Have your husband come here and read, so he can get a large overview of how poly works. Meeting a couple poly ppl irl would just give him a small slice of how it works.
Unless perhaps you go to a large poly meetup/munch in your area. However, i dont know how "out" your h wants to be...
Love withers under constraint; its very essence is liberty. It is compatible neither with envy, jealousy or fear. It is there most pure, perfect and unlimited when its votaries live in confidence, equality and unreserve.
~Percy Byshe Shelley