Lasting relationships

My boyfriend is 17 and I'm 15 we have been dating for 6 months this month, I know it's not that long but I really feel like we are going to last, we are so close and have such a good connection and friendship as well as relationship. We both lost our virginities to each other so we'll always be special to each other. 
Would love to hear about other people relationships and if they have thought they found 'the one' who turned out not to be the one