Why Is My Husband So Difficult!?

You're not alone.
Don't pay so much attention to the difficulty.
Don't use harsh words.
You can make things better by just ignoring. You will see how things get better and how it's a lot easier than you think.
Most of the time, this kind of behavior is due to pressures and difficulty at work. 
He's not 'letting it go' at other people who are more distant to him, only at those closest. There are few exceptions.
Think deeply about all the good G-d has given you and be confident that this will continue.