Hmm I only read about the first page, but here are some things you should consider.
1.) There is a chance she doesn't even have a bf. Yes, she can have a bf that goes to a different school, but theres a good chance she doesn't.
You being her "fake bf" can mean different things.
1.) She actually likes you / wants you to be her bf.
2.) She likes you as a friend and is being sweet.
3.) She's just joking/maybe messing with you.
(I don't know this girl so I can't say. I've never met her.)
If you really like her, you should tell her how you feel.
1.) You're scared of a bad out come. So is this girl worth all those days of never knowing? If you seriously like this girl, don't let her get away. Try.
(everyone gets unlucky, but sometimes you find really good people to love.)
2.) Do you just like the idea of someone liking you?
- I agree that I wouldn't want someone trying to take my "gf/bf". But if she likes you more than her bf it's obvious that won't work out anyway.
If she says no she wont go out with you because of her "bf", don't chase her anymore. You can be friends but go after a girl who is willing to give all of herself to you and make YOU her REAL bf! You deserve that much. Don't ever think other wise!
IF she really has a bf and you and her start dating. MAKE SURE she breaks up with him first.
You don't deserve to be "the other guy". Neither does he for that matter.