What should I do now? Please help :'(?

Well, I like this guy and we are like best friends but I don't know what I should do now. I used to be just another girl in his class until valentines day. On that day, he asked out a girl he liked and she said yesbut later that day my friend told him about how I have liked him since the first day of school this school year. The next day at break, he asked me to the school valentines day dance we were having that Friday.I said yes, of course. When I asked him if it was okay with his girlfriend, he said that she told him it was fine. The next day was Thursday and at our school, me and my friends have random hug day every Thursday. After school he kindly asked if I wanted a hug and happily I gave him a hug. Then the dance came. We saw each other a couple times during the dance and then we slow danced to Perfect by Hedley. Near the end of the dance, another girl who liked him asked him to dance and even tho he asked me to the dance, he said yes because he is a really sweet guy. It didn't bother me since, at the time, she seemed like someone he would never date. That night his girlfriend dumped him because she thought he was cheating on her with me.(After the hug and the dance, some people had said we were secretly dating.) He was really upset but I talked to him and made him feel better. A week later, he was asked out by another girl and he said yes. They dated for exactly one week but he found out that she was cheating on him and dating someone else but before he could do anything, she dumped him. This time he was majorly upset. I talked to him and tried to cheer him up as much as I could and soon enough he was over her. By this time, it was march break. She had dumped him the Thursday before the break started and now it was the Saturday before we go back to school. Me and one of my close friends were walking to another friends house when we saw him. He stopped and talked for a while but he had to go because he was headed to someone's house. We said good bye and kept going. After we had got our other friend, we headed back to near where we had seen him and he was there again. This time he stayed with us and hung out until the end of the day. Even though it was a Saturday, when we said our goodbye's he gave me a hug. The night of our first day back, I finally got the guts to ask him out but when I did, he said no because he didn't want to risk our friendship. :( Now it has been two weeks since I asked him out and he is dating the girl who asked him to dance at the valentines day dance. They are an okay couple but she is not a good person for him. She is really slutty and can sometimes be a *****. What should I do? I talk to him all the time and hang out with him a lot but I need something to do or say to win his heart and to prove to him I really love him. I say, "I love you!" to him all the time but it never seems to make a difference. Please help! Thanks. :/ :'(