My husband is always so angry

I'm so sad for him, and myself for having to endure his anger. Always angry over any little thing. He's going to turn 30 tomorrow and today he's been terrible, telling me he hates his job, he thinks I'm impossible to deal with, and when he got a birthday card on the mail from his grandmother he said "fuck that bitch". He had a terrible life growing up, his mother was handicapped and died 5years ago, his father was addicted to gambling and couldn't hold down a full time job and I has to remind him of his sons birthday tomorrow. He only has me in his life but his constant anger at the world is killing me