Dear god, girl, he was your childhood friend. Don't freak out. For one, a lot of people actually experimented as children and teenagers. For two, it sounds like a wonderful time. Since you're both married, well, I wouldn't get too many thoughts just yet. He was an immense part of your life in the past, quite a pillar, so don't turn away from it now, especially after you've found his reaction.
I think four marriages says he's interested enough in women to keep trying. Besides, as I had to explain to a friend of mine two days ago...
"No, we do not need to get a cute gay guy for me. We need to get a cute gay girl for me."