My DH was also against a homebirth initially, like most people are, because of the way we've been conditioned that healthy births take place in hospitals.
We read The Thinking Woman's Guide, we had long chats with the midwife- and now he's on board.
What helped very much to alleviate his fears about my safety was to make it clear that I wasn't compromising. It's not what I would LIKE to emphasize, but for every statement about how hospitals are awful for giving routine pit, epidural, episiotomy etc. I would say something like, "Of course if I went into labor early I would go to a hospital!" or "Thank G-d they can do c-sections to save a baby's life." He felt reassured that I wasn't taking any risks in HBing.
He still makes fun of extreme 'crunchy-mamas' but he really is pro-homebirth, co-sleeping etc.
Good Luck, and please fight for it! You don't want to be the 1/3 who ends up on a surgery table to have a baby!