I don't know if it will last; my stepson has had similar situations; we were looking forward to his marrying the last girlfriend and they seemed to suddenly break up and she moved away to another state and he took a new job! He has had his current girlfriend for 3-4 years now and before the last girlfriend there was another of that length, etc.

I don't think it is rebound. I think some people have an easier time when a relationship is over than others; kind of like when you changed jobs or move? If you are moving forward I think it is different from if you are "left".