I don't have any experience, but I did a little research, maybe you have already but maybe not.
From the Cystic Fibrosis Foundation (
Carrier Testing for CF - CF Foundation):
"Among Caucasian Americans, about one in 29 people carry one mutation of the CF gene. In other races or ethnicities, one in 46 Hispanic Americans, one in 65 African Americans and one in 90 Asian Americans carry a mutation of the CF gene."
From about.com (
What is a Cystic Fibrosis Carrier - What Does it Mean to Be a Cystic Fibrosis Carrier?):
"Broken down into odds, if the parents are both carriers, your child has a 25% chance of having CF, a 50% chance of being a carrier, and a 25% chance of neither having nor carrying CF.
If your partner is not a CF carrier, it will be impossible for your child to have CF because he can only inherit normal copies of the CFTR gene from your partner. However, your child will have a 25% chance of being a carrier, which would occur if he received the mutated CFTR gene from you. Meaning he could pass it on to his children."
So...first of all the odds that the BD is a carrier are low to begin with. And even if he were, there would still be only a 25% chance of your child having CF. So it sounds like really low odds to me.
Personally, would I still worry about those odds? Yes, but I'd try not to worry too much. It's all relative: if you hear someone's having a surgery with a 97% survival rate, that sounds really good - unless it's you or a loved one, in which case that 3% looms large. Similarly in your case, it sounds like a really low risk. But it's very understandable to be worried about it. I would say, allow yourself to worry a little but try not to take it too far, and keep reminding yourself about the statistics. The best thing you can do is just go ahead with the testing so you can put your mind at ease or arm yourself with information, and it sounds like that's just what you're going to do. Try not to worry too much until you get results back. And even if you did get a bad result, you should be able to meet with a genetic counselor who will be able to help put it all into a clearer perspective for you.
Good luck!