While it is possible to get the disease orally, I believe that the chances are just less. Not only that but i'm sure that during that time frame they probably abstain. I know that I do when the wife is going through that.well don't worry... the time will come when you won't have to do that anymore... been married 32 years and don't have to worry about that anymore.
One of the funniest Seinfelds was when Elaine's saxiphone playing boyfriend did that to her before his time on stage and couldn't play at all on stage afterwards... lol
I'm not far behind you, I turn 39 in August and will have been married twenty years in February.