love triangle, kinda sorta

Okay so... my best friend who has had feelings for me for a long time now has a girlfriend, he isn't crazy about her and still tells me he wants to be with me, but that every time he tried to tell me I had a different guy. He just came back from the military a week ago.... we hooked up and I'm not sure what to do now because I had also been Talking to someone. So now the whole situation is messed up. Help?