This is me, blowing my feelings out

I read manga, which is pretty much anime in a book. A lot of the stuff I read has relationships. It really gets to me at the end when something is achieved and they begin to kiss.
I realize that I might not ever have that, even though I am sure that I will get married someday, I have no doubt in that. It's just that I don't know if I'll ever feel the real love that you can only feel with one other person, with the man I'll probably marry.
How do know that he is the one that you defied fate to be with? I don't think that fate has your life planned out to where you actually get to meet this guy. I get heartsick for him, whoever he is, all the time. And those who have been heartsick before can relate to me, but unlike them, I do not have a boyfriend and have no crush at the moment. All I know is that my heart is already his, whoever he is. And it will be till the day I die, even if I never get to meet him.