I'm a tad ambivalent towards fate. Sometimes I believe in it, sometimes I don't. I always like to tell myself that things will always turn out ok in the end but I take a look at the world sometimes and its quite easy to see that for some people it might not turn out ok in the end. So I'm kinda arguing with myself on that point.
As far as Love and Fate together, I think that "Fate" is an assurance mechanism that people use when they're in love to tell themselves that they've found "The One". Its like a placebo effect, you believe it so it becomes true. If you believe you are fated to be together then its quite likely that your feelings are extremely strong and your continued belief in your relationship will help it be sustained.
Just my two pence anyway.