From what you've said at this point it doesn't sound like he really has the inclination to be poly. It sounds like he wants to keep his sexual options open. You say that he's 30 and has never been in any type of long term realtionship. This is all new to him then and I imagine he's adjusting to a new way of thinking.
How about you? Are you interested in other realtionships or are you interested in outside sexual fun? There isn't a right answer or a right way to be but it really sounds like the two of you have a lot of talking to do to figure out what you want. The thing is that what one of you wants may not be what the other wants. You are 2 individual people and although you share a relationship you might not have the same views on what you want other relationships in your life to look like and that's ok.
Everything will be ok in the end. If it's not ok it's not the end.