confused

pls help me this guy is driving me crazy ........ we met afew months ago and i fell for him madly and i still love him a lot ........ he also reacted like he is intersted... he gave attention to me i could feel it from his body language that he is intersted........so i approached him and described my feelings ....... but he told me no .......let me tell u one thing that our social relation is very respectable one .....i dont want to mention it clearly so i understood the reason for no at that time it was very hurtful though i decided to move on and i started keeping myself busy and we behaved like nothing happened but about month later he started behaving wiered and ignored me like hell and started flirting with another girl but i have noticed that everytime he talked to her but looked at me he is trying to make me jealous dont know why but i m damn sure he is but although i was badly hurt i didnot give any reaction ....... and then all of asudden he changed and has stopped flirting with that girl and is again looking at me just the way he used to with smile on his face and something inexplicable in his eyes ........ i am unable to understand whats going on in his mind and what should i do pls tell me