Here are my longest relationships:
1 year - we were too young, so really it didn't even wind up being a whole year. (And when I say too young, I'm talking 15 yrs. old)
1 year/ 3 months - May'98 - Aug. '99 Just gettin out of high school in '98. The reason it ended was because it was a long distance relationship and though I really thought it would work out, I had to end it. I just couldn't take not being able to see him any longer.
4 years/ 4 months - October '99 - Feb. 2004; first of all, we were off and on during that time. He couldn't make up his mind, so I finally had to let him loose (especially after admitting to me that he a girl pregnant!!

I think that would be an exit mark for anyone out there! At least I could only hope so.)