I believe in one true love. That's why it's called true love, it's unique - different than any other. You can't feel like that with any other person, because they are your other half. Only if you've experienced true love, can you see how incomparable it is to anything else, and experiences with anyone else. It's so far above the norm, there is no room for comparison.
It's silly to try to explain true love in a few words. No words have been created to equal the meaning of true love.