Maybe you haven't found the right person. People can confuse lust for love, they feel similar but are very different. I think young people, around my age (17), fall for people too easily, we've been taught that love will solve everything or at least help so even when we're young we're looking for it. I do think it exists but only if you're extremely lucky. Sometimes I doubt it to but I think I've seen glimpses of it.
Everyone who claimed to love me has disappeared so far as well but I don't think the reason is that it doesn't exist, I think it's because they've had to potential to love me but it didn't reach it.