Can you say why you knew he wouldn't like you?
It'll be funny now with him since you spelled the beans like that. I know it's hard to resit but hooking with someone you live with it's like hooking up with someone from work..never a good idea. Just keep talking to him like you always do, though try not to be flirty if you can because he's obviously not comfortable with you saying you liked him.
...for the 2nd time this year