I am kind of going thru the same stuff with my hubby. we have been together 10 yrs and I swear someone turned off a lightswitch with him. use to he held me all the time or couldn't keep his hands off me. now we rarely do anything at all. when he is home he sits in his little office and me in the living room. it is very frustrating. also he is a non communicator. he never tells me deep stuff and never has. *sigh*

if it is something you just can not live without then you are not a heel. I am sorry though that it might come to that after 21 yrs together. is he willing to get counseling? I would try everything possible before leaving.