I am with Gurps again here. I would go so far as to say that unless in your own head and heart you already know that you want to leave your partner, then it might be best not to expect advice on mumsnet about this sort of subject. I don't know what it is with all the people who's reaction is immediately "leave the bastard", I do think that there must be a significant number of mumsnetters who are in very unhappy relationships themselves, and project that on to others, or they are single themselves, and probably unconsciously, are jealous of those who are generally speaking, happy in their relationships.
OP if your initial reaction was (and it seemed to be) don't be ridiculous, telling me to leave him, we are happily married, but with the occassionally blow-up which your DP, for whatever reason, cannot deal with in the same calm way that you can, then I think that you probably are happily married, and that you may both benefit from some marriage guidance counselling - I know from personal experience, that if one partner tends to stay reasonably, calm during heated discussions/arguments, and the other doesn't, that the more angry partner can (in some cases) feel as if the calmer partner doesn't really care about them at all if it doesn't make them seem overly emotional too; whereas the calmer one can feel really upset by what is happening, but for whatever reason (and there can be many) does not feel able to show it. Both of those reactions are very common, and getting to the root of each persons insecurities (or whatever they are) can be extremely helpful in helping their relationships flourish.
Contrary to a pp's view (which seemed to be based on only her personal experience) some stressed, and/or depressed people can, and do, react angrily to situations that upset them, and if they are stressed or depressed, many many situations can make them feel upset/scared/out of their depth, etc. Yes, some people will withdrawer into themselves, but that does not mean that that is how stress and/or depression manifests itself in everyone else.
Obviously OP you can only cope with what you can cope with, and it wouldn't necessarily be helpful for either you, or your DH, to just ignore his outbreaks, and if you ever start being at all worried that his anger may become physical, or starts to impact too heavily on you (or your DC) then you would need to withdraw yourself and the children from that situation, at least until the issues have been properly addressed. At the moment you do not sound as if you are in that situation, and suddenly having to cope on your own (and with the DC) without the love of your life's support, company and love, can be a very bleak situation to be in.
My advice - for what it is worth - is to get yourselves on a waiting list for marriage guidance counselling, and an appointment for you and your husband to see (ok, almost impossible at most GP practices at the moment) his GP, or at least have a video appointment with his GP about your husband's ongoing stress/depression. If your DH isn't willing to do that, then can you write him (your DH) a letter for him to read when he is not in the house) explaining how his moods affect you, and what you feel you may have to do for your's and your DC health and well-being, if he is not willing to seek any help. Unfortunately, no-one on mumsnet can say what that should be. You sound very intelligent, and with a lot of commonsense too, which do not always go together very well, so I am sure with maybe a little time to yourself to think clearly, I believe that you will come up with the best solution for you, and your DC. However, I have great hope that your DH will see that him talking to his Dr will give you all the best chance in moving ahead as a loving and successful family.
If anything I have suggested here OP makes you think "No" that is not right for us, then please listen to yourself, and ignore me. Good luck, I will be thinking of you, and sending you the very best of good wishes x