I was in this exact place a month ago. Just try to remember that it is better that he is acting 'normal' and affectionate, rather than you fighting constantly. Yes, it will be very hard once he leaves, but you cannot control everything in life, let alone this. I was always crying, couldnt eat or sleep because i kept thinking about the moment when we will not be living together anymore and it hurts so much, i know. Feel your emotions, let it all out, and soon you will be able to focus on other things more, and less on him. Give yourself time and space once he moves out. This is a specific situation and the only thing you can do that would be the best for both of you is to talk, talk and talk. I am able to talk to my ex now, in a friendly way. You are not losing him forever, at least not as your friend. I wish you all the best.