Anyone else's hubby nervous?

This is our second pregnancy, babies number 2 and 3 and they were completely natural....so a little bit of a shock needless to say. We were both excited right away, but I feel like the more the weeks go on the more freaked out he gets by the idea. He says he is excited about them, but I just have this gut feeling that he is totally freaked out about the idea of two at once. We have been together 10 years. I know him and he just seems off. Is this normal??