Because I think when you fall for a girl, you somehow imagine that your main mission is to protect this girl from the rest of the World, to be her guardian and protector, to be her man.
But once you love a boy, you put this boy in the very center of your whole universe. Every single choice you make is somehow influenced by his very existance, by his words, his opinions, his lips, his penetrating and pure eyes that you can only see from a simple, old and unchanged photograph.
This boy suddenly becomes the pair of lens that allows you to see a much more colourful world than how it actually is. You feel every single glimpse of happiness you could ever feel, all at once, like a storm of strong emotions. You smile unconsciously every time your thoughts go directly to him, even though you never saw his smile in real life. His voice, still completely imaginary to you because you also never heard it at all, surprisingly sounds more beautiful than the most beautiful of the songs you have ever listened to.
You promise yourself this boy will be the only One in your life, the Chosen One, the Love of Your Life, the Sun and the stars, the Moon of your night, your everything. You promise yourself that you will be completely his own, his love, his sacrimony, that you will do everything to be his everything. You picture the most beautiful scenario to the moments you would be together as one, as two, as infinite.
It means nothing.