How do you stop liking your friend (ex)?

I'm a guy and my (girl)friend who i use to like(still do a lot) use to cyber date cause she moved away and we kept in touch and had a relationship. We broke up but decided to continue as friends. I still love her but as time progressed, she proved to like me less and less. She came to my city to visit her father who still lived in my city. We decided to meet up at a pizzeria since we hadn't seen each other for a full year. I saw her,gave her a hug and asked her to come to my place and she said yes. I live with my best friend (which ironically was her ex) and they had gotten acquainted again. After much fun and a little bit of awkwardness she had to leave. A couple of days later my best friend told me that she had been flirting with him for a couple of days through text even though she told me she didn't have time to text. So now i want to forget about her cause she cause me a lot of pain and lies. The whole story is much longer but that's the main key points in it's entirety. Personally i think she has been using me for a shoulder to cry in and nothing more. Advice is greatly appreciated =\