Do you feel that he has already left the marriage, emotionally?
A few couples can get by without much sex, if their sex drives are similarly low, but the complete lack of affection you describe indicates real trouble.

Can a sexless marriage truly be happy? Marriages do not feel happy or sad - people do. The way you write shows that you are deeply unhappy with your lack of a sex life. That is not going to improve unless something changes, though you may become accepting of it and settle for an unfulfilling relationship.