I'm thinking your husband had a gut feeling based on preconceived notions. He'll need some time for it to settle down so that he can make up his own mind and his own feelings, and seeing your friends being happy should do that.
I'm not sure how you can help him specifically, I think he'll need to ask himself questions, such as what makes him uncomfortable, and how to rebuild his belief system if he decided to do so. By which I mean, if he thinks a poly relationship can't be a good, healthy, loving relationship, but he sees your friends in a good, healthy, loving relationship, he needs to come to terms with the fact that his premise was wrong, and that might be hard for him.
I wouldn't expect him to be fine with it right away if he had trouble with the idea at first. In my opinion, he just needs some time, and to see how he feels then.
Last edited by redpepper; 05-21-2012 at 04:47 AM.