BFS, I chose my midwife the first time around and then had to come to grips with the whole homebirth idea. :) Once I learned that a birthing clinic is not any more safe than a home birth midwife with all of her equipment, I was fine with it, but my husband was a little more anxious and my family thought I was nuts. Thankfully, my sweet midwife came to the apartment after hours and talked to my husband about things until he felt okay with them. She talked about what we would do in various situations and what the dangers were and how she could handle them. Then we took a 12 week Bradley birthing class from a woman who had birthed 5 children, the first in a midwife clinic and the last four unassisted! He came away with so much information. By the end, he was a total home birth advocate and, even after the trauma of transfering to the hospital, etc. he's up for doing it again! Also, I think, seeing that my midwife did not take any chances and we did not transfer in an emergency situation (but to avoid one) probably helped too.
I'd say, give your guy time. Also, if he's up for it, maybe watching the "Business of Being Born" and/or casually bringing up studies on home birth/natural birth/etc. safety. If he's a reader, maybe he'd read some good books or articles on the subject. For my husband, he was in awe of the body's natural process (as taught in the Bradley class) and got why it was important to avoid the interventions common in hospitals. Just because he's apprehensive now doesn't mean he always will be. Also, good men take the responsibility for protecting their family very seriously. Possibly, the idea of taking more responsibility for that (rather than leaving it in the hands of a doctor/hospital) probably is scary for him. Maybe if he could talk to other home birth dads, he might see that staying home IS often more protective.
I'm so happy for you and your homebirth!