Unrequited Love.

So I a thing for this girl, I have “off and on” for almost 8 months. What I mean by off and on is that for periods I would completely ignore the fact that a thought she was the cutest/hottest thing and wanted to have a relationship with her. My problem is that she’s told me multiple times she’s straight so I know it’s likely never going to happen. I want to keep our friendship but I don’t want to lie to her. On top of that we are polar opposites. What should I do?