I've been here, as many others have, and can confidently say that it is no fun. My situation was only compounded by the fact that my friend shared my feelings, as he is bisexual himself. We couldn't be together because we are both in long term relationships with women that we weren't willing to end to chase what "might" be.
I'm going to be frank here. If you're anything like me, and anything like basically everyone else I've seen in this situation, things are going to get worse long before they get better. I doubt your feelings will go anywhere, and the fact that you live with him is only going to make things worse.
So what do you do?
Decide what you want. This is going to need to come before anything else, and you need to be honest with yourself. Do you want a relationship with him, or are you truly ready to do what must be done to allow your feelings to die, and your friendship to resume later?
You're probably going to have to tell him the truth. There is really no way around it, and the fact that you live together really complicates this I think. He's your best friend. Sooner or later he will very likely notice your changes in behaviour toward him. If you try to simply avoid him, he'll notice. If you try to be less friendly, or less open, or less available, he's going to notice.
When (if) you decide to speak to him, I would be forward and transparent, on all fronts. It is the only way that he will be able to trust what you say, and that the two of you can work on this thing together. Tell him how you feel, how scared for the future of your friendship it makes you, what you want. You say you just want your feelings to die, and I must admit I don't entirely believe that. More likely you want him to reciprocate, but don't think that is a possibility, and thus have moved to option two which is letting your feelings die. I can say in my experience it doesn't matter how much you wish them away, your feelings with fight you to the death tooth and nail, and if you try to smother them while maintaining this incredibly close relationship, you're going to destroy yourself from the inside out. I say this because that is exactly what happened to me.
Be prepared for the worst. Things between me and my best friend are good again now as we've managed to resolve our situation. However I went through hell and back to salvage this friendship in a process that took well over a year. We fought a lot, said a lot of not so nice things to each other, and really got to see a side of one another neither of us knew existed, or ever wanted to see. We only managed to work things out because we spent about 5 or 6 months with absolutely 0% contact. This is not an option for you, since you live together. If your friend takes the news poorly (as my friend did), you don't have anywhere to hide or get away from him. I know this sounds really awful, but I would prepare for one of you to potentially move out.
I highly doubt this is the news you wanted to hear, but it is the truth. I do not claim to be the master of these situations, but I spent a very long time living it, and spent an equally long amount of time gathering information about it. When best friends fall in love with each other, especially same-sex friends, things often come to this crossroads you're at now. If he is truly your best friend, he will accept you for who you are, be flattered to hear you feel that way, and likely sad to say that he cannot reciprocate them and give you what you want (assuming he doesn't reciprocate your feelings). You really need to not give your feelings room to breath, or grow. You cannot give them any hope, or they'll latch onto that and drive you insane. The only way to do that is to do the scary thing, and tackle this problem head-on.
Whether you take my advice or not, I hope things turn out for you and your friend. It was easily the toughest period of my entire life thus far (I'm 24), and I know how difficult / horrible it can be.
Best of luck man, take care.