The answer is very simple because it is in your last paragraph - you say ‘I would like to take the job part-time, or for a bit’.
Taking your husband out of the picture, the reality is this: we are in the middle of a pandemic, the economy is suffering and will suffer and your family has no guaranteed income from what I can gather. Minimum wage or not, the job provides a guaranteed income. There is no guarantee another job for either of you will come along soon (unless you are virology researchers or otherwise medical). So here is a chance for some guaranteed money to come into the house. Even better, it is a job you would like to take.
Ask yourself this: why now, when you have the opportunity to work outside the home, to meet people outside the home, to earn money of your own, is he suggesting that you draw on your pension (your future security) and work on your business? Is this a particularly timely moment for your business? That would be the only reason to consider it. Otherwise you can keep it ticking along in the background until circumstances are better.
The lie is in the fact that he has brought the children into it. There is your emotional manipulation right there. These poor neglected children will suffer if Mum goes out to work. He won’t get to do what he wants to do. Well, let me get out the world’s smallest violin. His concern is not about your business, it is about his life changing even more than it has. (I do have some understanding for that, but the reality is that many, many people’s lives have and will change, and you are being proactive and making sure that you take the concrete opportunity you are offered; I would do it, and quite frankly, there might come the time when he also needs to take a job which detracts from his business time because paying the bills is more important).
The household chores can be split, he can work on his business in and around looking after the children and doing his share of the chores. The children will soon be able to see their friends again.
So to him you say something like, I have accepted the job because it is more important for the family to have some financial security over the summer and for me to retain my pension.
Then no more discussion about it, but focus on what needs done regarding childcare and chores to make this work so that you are not left with the double-burden of work and domestic stuff. This is the time for your assertiveness.