I think Tim Minchin summed it up brilliantly.
I do love my dh, we have been together 11 years since the age of 17yo and I love him deeply and adore him.
But I do not believe in 'the one'. I believe that you are compatible with many other people but you pick one and you grow to love them and through shared lives, shared experiences you (hopefully) grow closer. I hope my relationship with dh lasts forever, I married him with that thought in mind. But if one of us (heaven forbid) dropped dead tomorrow, I hope the other would, in time, have another fulfilling relationship.
I feel more secure not believing in 'the one'. I know that relationships take effort, have their highs and lows and that they aren't automatically perfect or he's not the one. I feel better knowing it was dh who picked me, despite my flaws not 'fate' - a concious decision on his part. I think sometimes believing in 'the one' can be dangerous in keeping someone in an abusive or just failing relationship because that person has been designated as 'the one' so you can't end it, you have to put up with it.
Dh believes the same as I do, in case you were wondering 