Deep down, your boyfriend knows you are right. He hates his job, but he keeps working because he knows he has to. The truth hurts, and because you're telling him the truth, you're hurting him. But sometimes, you've got to do just that to support someone.
He's not angry at you. He's angry at the situation. He's angry because he feels powerless to change it. You're never going to make him feel better, but you need to do what you can to keep him on track.
My advice is to just give him the facts. And here are the facts:
-It is much easier to get a new job when you already have a job. Hiring managers are very reluctant to hire someone that quit a job without having a new one in place. They want to see continuity of employment.
-You need the money to live. Because you live together, his decision to quit affects you both. You will have to live very meagerly for a very long time if he quits without something else in place. He will be exchanging work misery for poverty. And poverty isn't fun for either of you.
-The rest of his life is going well. He's got a great girlfriend, friends (hopefully), interests (hopefully). He can't let a bad job make the rest of his life bad. He needs to focus on the positives right now.
-It does not take all day to job hunt. If he spends one to two hours a day looking for jobs and applying for jobs, he will be able to find one soon. An extra six hours a day won't make a big difference.
You're doing the right thing by talking sense into him. Keep talking sense into him. Reminds him of the facts, and tell him that it'll be over soon. And just be patient with him. Being trapped in a bad job is very hard.