You gotta make yourself available to him. If you let him see you as 'one of the guys' he wont know that you feel any differently.Try dressing a little sexy for him tell him you think he's cute and just flirt with him. Guys dont understand subtelty. Go for it!!
He probably does not have a love life at all and is hoping that you will (a) Feel sorry for him and (b) Take the initative. i.e. It's you that he really wants.
Take the advice from the other poster, dress really sexy for him etc.
If i were you, whenever he says something about what he did wrong in a relationship, say "Well I wouldn't care...I would love you all the same" very sweetly and flirtaciously and MAYBE he'll take a hint.
tell him. tell him. tell him.
life gets more interesting every time you tell people how you really feel.
You need to get him drunk. Wear something sexy and let your panties stick above your belt line. Or, let him accidently see you in your panties or naked.