He wants to double-date my room mate and I

I get very worried when I start think about what this guy is up to.back here in my univwersity,I stay with my best friend in the same hostel room,she is my room mate and becos of what we see guys do to their gurls,we decide we aint going to date and we have never dated.she is a bit taller than I am and well a year older.with this mixed hostel arrangement,oue neighbour is a boy who smokes a lot.he is handsome no doubt but we are so closed to him.a week ago,he started advancing passes at me and I refused though,how ever on this nyte,we had a short kiss after which I stopped it and told him this joke wasnt going to go any where because I aint going to date him.he keeps trying to convince me and ask me to trust him but even if I could I hate the smoking part and cant go against my decision of not dating.I travelled and coming back 2days back ,he told me he joked about being in love with my room mate and all.I told him we are friends and nothing more.he says he is beginning to fall in lve with me.well,yesterday,my roommate was in his room the whole day and he also made passes at her,telling her he loves her.my room mate told me and said she hopes he is joking because she cant go against our decision of not dating and well this keeps me confussed and guilty.confussed becos I dont know what this guy is up to and guilty because I didnt tell my mate about him having made passes at me too..this is the par I get confused,I dont want to date him for that I know but what I dont know is why he is doing this to us[bestfriends and roommates ]at thesame time]please every one please I need advices on what to do I am so confussed I dont know what is wrong and right anymore pls can some one tell me what he or she thinks???thanks