Going through hell

I can't believe I did it again!! I'm so upset! These 4 characteristics (Explosive rage, being extremely nice, not liking people and pity) exactly describe my current 'relationship'! I'm in so much pain and anxious all the time; he puts me on this incredibly high pedestal only to kick me off it any time I don't do something the way he wants me to, any time I say the wrong thing or don't talk or talk too much or don't do 'what we agreed on' (the list for this is so long I can't remember it!). He tells me that I'm beautiful and intelligent and the best person in the world, talks about us getting married and having children, but he has no patience for me; if I don't do things the way he expects me to, he gets really angry, screams, shouts and swears at me, tells me that I'm the 'stupidest smart person he knows' and he also said I was too stupid to go out with. He regularly screams at me and is mostly remorseful afterwards, he says that my heart is too big. What does he mean by that? His behaviour is so inconsistent that I feel like I'm walking on a minefield. I'm constantly anxious and started smoking again (cigarettes) which he despises. He is not a narcissist this time but definitely a sociopath if I go by your description above. I love people and he says he hates people; that people are stupid, undeserving and useless. He expects everybody to behave his way, if you don't, then he deems you disrespectful, stupid or nasty. I don't understand how he can dislike people; he is in the Army and he is fighting for people. But he expects them to be grateful and live life a certain way. He gives orders, if I ask him to talk to me nicely and in a more lighthearted way, he goes mad. He gets 'hurt' by tiny things but he says the most hurtful things and expects me to just shake his comments off. He expects me to drop a conversation if he doesn't see the point in us talking about that topic anymore, or else he goes really mad. He walks around with a frown and judges people all the time, mostly on their looks or how they walk (too slow, wrong side, stop unexpectedly = stupid, useless people). I don't get it
because his biggest fear apparently is dying alone. Yet he alienates people around him. He definitely
alienates me. He has been in the UK for over 1.5 years and has no friends apart from me.
He only has me and the people he works with but he doesn't socialise with them because 'they only want to talk about work'. He has no ability to change the topic of a conversation in a nice, tactful manner; if he says 'drop it' and I don't, he will give hours of hell, attitude, swearing and shouting. I feel so lonely and desperately want him to love me but I am beginning to think he doesn't know what love is. I'm so upset.
I'm so confused all the time, he tells me that he knows he shouldn't get angry but I could do some things to prevent him from losing his temper. To me this feels like a cop out, that he doesn't want to take full responsibility for his actions. I'm so confused, I don't know where do I go wrong, but he says I do all the time. Am I in a relationship with a sociopath??