was sixteen and going out with a 21 yo. I was his first gf, he talked of the future, waiting for me if I went to uni, etc etc. He was fairly immature, I was more mature, we never slept together fwiw.
So as time went on the relationship sort of ran its course as happens at that age, I no longer felt the same about him so I ended it. We stayed friends for a bit but then contact fizzled out really.
Fast forward about fifteen years and I happen upon him on an email list, so I send him an email to say hello, how's life, etc. We exchange a few emails, I tell him about then dh and ds, he tells me he still works for the same company and is still living with his mother and has never had another gf because he just hadn't met the right one. 
Then one night we're talking on Skype text chat and he suddenly says "it's amazing that we are still able to have a civilised conversation all these years on after having such an awful break-up. I was 
thought it was just a teenage relationship which had just run its course. he obviously thought differently.
ten years on and he still hasn't had a gf, well apart from one which he went out with for about ten weeks and posted every detail about their relationship on fb about how it was the best week/three/five/ten weeks of his life and then how some people needed to deal with their issues before getting into relationships. 
and still lives with his mother.