what you are describing is called dissociation. he is simply dissociative. read about it.
i have seen my husband changing from the most loving and caring guy who gave me a hug to someone who right in front of my eyes turned into an ice cold fish totally without any feelings. by now- i know how he is doing, i can see it everytime it happens. he still doesnt know or can control it, but he is ready to at least believe me when i say it happens. then he grounds himself and tries to get himself back. read about dissociation and grouding exercises. no joke, they do help.
i also see that you are not ready to give your life up to the "shit". thats a very healthy statement. you dont have to leave him or stop loving him, but if you set your personal boundries, its very healthy. you need to. you have a very sick person at home, not his fault, but very sick!
everything is always okay in the end, if it's not, then it's not the end