Has anyone ever waited for someone for a long period of time and made the relationship work?

I am totally in love with this man who I dated for 3 months and is currently unavailable because of distance, time, and current living situation. We broke up about 3 months ago and I have talked to him a handful of times since then. Every time we talk we discuss how much we want to be with each other and that if things were different then we could be. I want to wait for this man for as long as it takes, but is it possible to make it work? Am I just going to cause myself more heartache? BTW he can't date anyone during this time.... so he will be available once his situation changes. Which could be up to six months, a year, or even 2 years (although doubtful that long). Any advice.....