No, I don't want that! Mikasa finding another man...?! I want her to think about me and no one else for the rest of my life! Even after I die... I want to be at the front of her mind for a while! 10 years, at least!
This is what happens when you tried to be a man, but your female friends all saw how small you are, laughed at you, and convince you that you're better off just being a girl like them.