I love you also means I love you more than anyone loves you, or has loved you, or will love you, and also, I love you in a way that no one loves you, or has loved you, or will love you, and also, I love you in a way that I love no one else, and never have loved anyone else, and never will love anyone else.
http://www.goodreads.com/quotes/43334-i-love-you-also-means-i-love-you-more-than