We live together, but I can't be with him... (please help me!)

If anyone has any idea on how I can prevent my heart from breaking, please tell me it as soon as possible...
Here is my situation. I am an 18 year old student who arrived at university about 3 months ago... having never been to this city (Belfast) before. On my second day in town I met a young Irish boy.
We get along really well and we're really into each other (or at least we were). But he lives in my hall, and we share a kitchen, which complicates everything.
Long story short, we almost started dating my second week in the country, but then he said that because we lived on the same floor there was too much risk involved and if anything went wrong we'd have to deal with it until May... and, well he's right, but as far as I'm concerned him saying this WAS it going wrong (he doesn't know this about me).
Six weeks came and went, we got closer, he got flirtier, and I started losing my mind.
So, I made a big mistake. Yeah, yeah, I know... I brought the conversation up. (To my credit, several guy friends told me I should... do men not understand themselves or something?)
He told me, "Sadie, this is tough for me, because I really really like you... but I like my lifestyle here and I don't want it to change". It gets worse - I told him "you realize this is the last call, right? Take me or leave me... You can't try again in the future." (Why, oh why was I so stupid?)
This was now another 6 weeks ago and I'm beginning to slowly fall apart. He treats me so well, he walks me home when I'm too drunk (uni life!), he takes care of me when I'm sick, and he has done so much to help me feel comfortable living in Belfast (he is from Northern Ireland - I am from Kenya and have been frequently homesick). And what he doesn't seem to realize (or maybe he does) is that these actions make me absolutely crazy about him.
I don't know how to react when he keeps flirting with me and I don't know how not to send 500 mixed signals. I'm especially worried about my stupid declaration.
And I know I've been sending him mixed signals. Last Thursday when I was drunk, after jumping in about 20 puddles while he was taking me home I suddenly started talking about the upcoming vacation (in 2 days I'm going away for 2 months - this may be a blessing in disguise, but anyway) and I started saying how tragic it was and how I was going to miss everyone. He said something really sweet about how hard the vacation was going to be. About 2 minutes later I told him I wished he were an asshole, and then I refused to explain why. Then over that weekend he read a 1 paragraph long note that I gave him which basically told him he was my best friend in the entire country (he is). I know exactly why I did everything, but he must think I'm a space alien by now.
...And so last night I hit rock bottom when he was sitting there in a lounge chair with his arm around some random girl I'd never seen before. I ended up feeling flat out nauseous and had trouble saying anything to anyone. I don't even know if they went together or something, one of my friends told me they didn't, but whether or not he realized it she seems to be quite into him (yes, I know I'm overreacting - my reactions right now are shockingly emotional even though I've managed to avoid coming straight out and telling him how much I care about him or anything, I'm playing the ice castle card... ah it all is messed up)
At this point, I need to either get over him (I have a psychological block from doing this, as I really don't want to get over him) or get him to change his mind (which is changing him, and that's not a fair option), or I don't know... is there a third option? I'm in sheer agony on this issue.
What can I do to get him to see that I won't try to dominate him or change his lifestyle and I just want to be closer to him? I don't know whether I'll be able to get over him when I see him every day and he keeps being so adorable and he keeps taking care of me every time I get sick.
Be firm on me, kick me around if you need to... right now I need honesty.
Thanks guys.
Sadie

what a jerk.

i guess it turns out he wasn't the nice guy you thought he was. that happens quite a bit more than you would think.

you'll have to find another friend and just stop contacting him.

sorry. it's happened to all of us.

Wait, why is he a jerk?
Also, I can't stop contacting him, as we live together...

"Sadie, this is tough for me, because I really really like you... but I like my lifestyle here and I don't want it to change".

Maybe in time he will change, but probably not right now. Don't pine over him, and move on.

I don't think he is a jerk. He made his intentions clear. If he was a jerk he would have had sex with you, and then said the above. You are in a vulnerable position, homesick and lonely, in a new country, and at a uni. You would have been an easy target.

Enjoy your vacation, move out of that building, and find someone else to be your friend - preferably someone you don't want to have a romantic relationship with. Don't hang out with him again, until you develop your own social life. When you find your own friends, and if you think you can handle it, give him a call just to hang out.

This is kind of funny.
He just went home for the break, right... I was basically terrified of the moment when he was going to leave.
As he's getting the last bag out of his room (I was standing there watching him do that, cos he'd called me over to tell me he was leaving) I opened my mouth and blurted out (I had a curious tone rather than an accusatory one) "hey, are you dating that girl you were with last night?" He made a face and went "nah". I felt a guilty sort of relief and said no more on the subject.
So we talked about other stuff for a bit, and then he goes to give me a hug. We hugged tightly for a few seconds and then started talking again - but he wouldn't stop hugging me at that point! I said "I'm going to miss you", he said "you'd better", I hit his back gently and called him a shmuck, and then he started telling me he hopes I have a really really good time in Kenya. (Around this point we stopped hugging, but he still had his hands around my waist, so I left mine on his arms)

I thought I'd feel like hell right now. Turns out I actually feel great, and this is inclusive of the knowledge that I'm not going to see him for two months.
What a difference 10 minutes makes...

Hopefully the vacation will clear everything up in at least one of our minds, but I'm not going to spend the entire time trying to psychoanalyse someone on the other side of the globe...

Yeah, enjoy your trip home. It comes just in time to prevent yourself from making a fool of yourself. When you get back, I think you should minimize your contact.