It's difficult to say without knowing what you are paying in childcare every month.
In addition, is there any risk of your husband's business going bust or what would happen if he was incapacitated.? Would your employer consider a career break at least if the worst came to the worst, you'd have the option of going back to work. Likewise, given your kids age, I assume one of them will be starting school soon, would reduced hours/personalised hours in your current employment an option worth considering?