My two cents:
This is such a hard issue. I feel like one of the "lucky ones" - I found an incredible man who is completely willing to not only accept my CF, but accept that it's a major part of both of our lives. While we were engaged I was in the hospital 3 times, and in our almost 3 years of marriage I've been in 7 times (I was out for all of 2010, but other than that I've been every 3 months or so). My husband helps me flush my port, gives me CPT when I ask for it, puts up with me being away for 2 weeks when I'm in the hospital (our hospital is 4 hours away), and is always sweetly willing to hear me vent or cry when I need to. My only wish in regards to CF and our relationship is that HE would talk a little more about his feelings - he obviously has plenty of his own fears and frustrations in regards to CF, but doesn't usually talk about them. (He's that way about most things - a pretty introspective guy.)
Before I got married, I had two "almost" relationships that I suspect ended because of CF. Before we were dating, my husband found the very alarmist wikipedia article on CF and did freak out a little - later, I asked him what he thought about it, and he said that it really scared him but that he liked me enough to keep me in his life. Before we got engaged, we had several long talks about CF and the more serious implications - that we may not be able to have children, that I may become very sick and require a lot of care, that I could die young, etc. He was a trooper through it all and did not hesitate in deciding that he still wanted to marry me. I felt enormous guilt while we were engaged about subjecting him to all of "my problems" - but I realized before we got married that that was not my choice to make, it was his. And, in the almost 4 years we've been together, he has handled it with flying colors.
Before we were dating exclusively, he asked me on a date (our second or third) and I ended up canceling at the last minute because I was sick. I felt horrible doing it, but I knew that he needed to get a realistic understanding of what my life and my capabilities were. He was really bummed and frustrated about it at first, but later he gained a better understanding of my limitations, and while we were dating he was always willing to come over to my place and watch a movie instead of going out and doing something more strenuous, or come play games with me while I did my nightly treatments.
Creating a strong and solid relationship is tough in any situation, but especially hard once you throw in CF. There's a lot of nuances that you have to figure out - how comfortable YOU are sharing your life, how comfortable they are being a part of your life, etc. etc. etc. I talk to my husband often about CF - I mean hello, it's a huge daily part of our life! - and when I am having a tough time, I'll often "vent" a little or cry (I am a watering pot!) to him about it. I do take care never to take my frustration out on him or our relationship in any way, but we are very open about CF. In all honesty, we have probably the strongest marriage I know. We get comments all the time on how we've been married for 3 years now but still act like brand-new-newlyweds. We've had some really tough times - our engagement in particular was 7 months of sheer torture (we did the whole thing lost distance + I was in the hospital three times... bad combo!), but I truly feel that working through the difficulties together has made our relationship much stronger than most.
Good luck (to all of you!). It's so tough to feel like you don't have anyone to support you when you are already dealing with the isolation of having a disease like CF!