I've fallen in love with a straight guy?

[19FPWLDJ]

I'm 16 and I'm bisexual and I've fallen in love with a straight guy at school. I'm not to sure if he is exclusively straight though or if he is at all. He went out with a guy for a while a few years ago and then he said he missed him after all. He says to everyone he is straight even though he's came out a few times and then denied it. His facebook profile also says interested in men but he said that was a mistake. He doesn't act gay but there is little signs. He's in only one of my classes and once a few weeks ago he turned around to look at me for a second but he's not really doing that anymore. I really like him but I don't know what to do. Any advice?