If his moods and temper have gotten worse since the kids then perhaps he just feels trapped to some extent? Especially if he hates his job. For some men family life sounds good on paper, or they do it to make their wives happy, and then later make everyone miserable because they didn't want that for themselves in the first place. Some men are just passive aggressive and resentful of the attention babies get. Who knows? Tons of scenarios could be possible.
If he's always been moody, though, and it's recently getting worse I would talk about seeing a professional. It could be anything from depression to bi-polar disorder or anything else, really. The psychiatrist will figure out what seems to be going on. It may require lifelong drugs, or short term drugs. No telling. Maybe going in and talking as a couple could help put your marriage back on track? There is no stigma or shame in looking for help these days. It's better to talk it out with a professional than to cover it all up with some booze and nasty fights.
I would start by opening a dialogue with your husband and ask him what's truly going on. Be patient, be kind, don't judge, and LISTEN. Be proactive, and if he does actually talk to you about what's going on in his head, be compassionate and work TOGETHER to find a solution so things will be happier and better for both of you. It takes a lot for some men to open up and yelling and treating him like a child will only serve to clam him up more and likely make him into a bigger baby.
I empathize with you on your situation. It's very hard to work and raise kids without the support of your spouse. You guys should be functioning as a team, and you shouldn't have to shoulder the bulk of the parenting because he's busy having little meltdowns.
Get to the bottom of this as kindly as possible! Best luck to you, hun!