How to get a girl who got a boyfriend?

facts...

-she got a boyfriend they had been dating for almost 2 years...

- barely see each other.. idk if they text each other alot but whatever

-she asked me if i got a girlfriend it was out of the topic and i said no.. wonder why she asked me that.

- i asked the same question but she said she does have a boyfriend nothing more nothing less

-when i talked about prom she mention him again pissed me off but i acted neutral

- it was my 5th time talking to her when she mention her bf -_-

-that was this monday

-tuesday she seemed busy i talked to her on the morning maybe for a min..

- saw her today i didnt talk to her bc she seemed busy...

- i wont deny im better looking than his boyfriend and so many girls want me but this girl seems confused

- i know she got a kind of attraction towards me since i had seen her talking to her friends and then look where i stay at. it happen more than once

- i felt like she is avoiding me today idk why but whatever..

-im a shy dude so im not really good at making conversation..

- you might be asking why she seem busy is because this a semester that you have to finish a class in 2 weeks meaning a whole semester in a week...

- saw her holding hands with his bf 2 months ago a friend saw then together twice

- you can tell they barely see each other..

- my friends said i make myself look obvious when i got a crush on someone

what do i do?? idc if she have a bf i still want her