I was thinking about this a bit more.
I think as we all grow early (especially early 20s) and our lives change so much (in school our whole lives and then BAM! it's time to be an adult and work and live our lives independently and look for a spouse maybe) we all go through this self-reflection.
I think almost all of us have said "Gee, there are so many smart, interesting, wonderful people out there. With all of those people, why would someone chose to be with ME, with CF????" For many of us it might just a passing thought, or for some this feeling might last a while - while we find ourselves as adults.
I'll give you an example that really helped me. My boyfriend is from overseas. This doesn't make me see him any differently - he's still really smart, motivated, funny, caring, cute, and a great overall person. But we have encountered a few stumbling blocks because he is foreign (cultural differences, language barriers, and his ability to stay in the US). He asked me once why I bother? I could date someone who is from the US and not deal with these issues.
It took me by suprise because for me, I don't care that he's from overseas. Sure, we have some issues but it doesn't change how much I care for him. And all of our troubles are well worth it.
He has lickened my CF to this. Sure, there are issues but it's only a tiny part of who I am. And he'd never not consider dating me because of that. Granted the examples aren't exactly equivalent (he's not going to die early because he's foreign), but the general idea is.
This really helped me gain perspective on why peopel are wiilling to date/marry those with CF. It's not who we are. It's just a part of what/who we are.
Hope this helps.