My hubby and I were in the same situation, I want to know, and he doesn't (we are not pregnant yet - but trying) I just told him that I am going to find out, and I don't care if he does or not.. Then as a joke (kind of) I told him that I would also not keep it a secret, so he could be in the room with me and find out.. Or he could hear it through the grapevine, either way he is going to find out hehe.
He finally gave in (he knows that I can't keep a secret, and I hate surprises... I still snoop at christmas)
anyway, hope you can talk your hubby into it. Good luck.