Once you fall in love for the first time I don't think there will ever be a time again that your not in love with someone. It may not always be the same person but there will always be someone special in your heart that you love. That person may be your significant other or not. It may be someone you had a fling with or not. They may even just be a friend. Even if you don't have many loves in your life you will never stop fully loving someone until you have someone else to love in their place because people are made to love and to not love anyone would be more painful than not being loved by the one you love.
