How do you work out a man's mind

Sooo, basically it's this. We are in a long term relationship. He's never been one to show his emotions but now things are a bit rocky between us.. Actually they're falling apart atm. We literally can't seem to have a conversation without arguing, which ends in him always saying 'leave me then' or 'I dont care'. But then an hour or 2 later he will act like everything is fine and ask what I'd like to eat!! I know we all say things in arguments but he says this all the time, and it's the way in which he says it makes me really think he means it. We've been together 7 years, live together and have a little family together so I'm not gonna just pack and leave and give up on all that over these statements of his UNLESS I know for sure he means it. I can't get straight answers out of him because he doesn't do these kind of conversations. But I'm fed up of guessing what he fucking wants! Like last night for example, after yet another row and him telling me he's not happy etc (the usual shit) I just went to our bedroom out of the way for a bit of peace and quiet. He then makes little excuses to keep coming into the bedroom. Why?