OP, what a horrible shock.
Assuming your H has been in charge of the bills and admin up to now and if general disorganization on his part has been a problem, then you need to take the reins.
After you've dusted yourself off (which you need to do ASAP), you need to take the time to find out where exactly the money has gone, who the creditors are.
Get all the bank statements you can lay your hands on.
Get all the credit card statements.
Get all loan statements (car loan, etc).
Identify subscriptions and any charitable donations.
Identify streaming service bills (music, media).
Identify phone service and phones.
Identify optional expenses like coffee/ lunch at work/ birthday or Christmas gifts/ entertaining friends/ eating out/ attending shows, cinema, horse racing, moneybspent on outings eith kids, misc events.
Identify private school fees.
Identify the holiday budget.
Identify gym and club memberships.
Identify services you pay others to perform - gardening, cleaning.
Identify money spent on nice gadgets - gaming devices, coffee machines, newer model cars, TV, etc.
Identify money spent on hobbies - bike, crafting, running gear, sport equipment, pony, etc.
Identify lifestyle expenses like clothes, shoes, bags, ties, branded items, etc.
Identify money spent on landscaping, home decorating, etc.
Identify memberships - zoo, NT, museums..
^ These can all be trimmed significantly.
Identify your essential bills - mortgage, house and car insurance, utilities.
Tot up your fixed expenses.
Set a low food budget.
Look at school fees if any.
Identify where savings can be made immediately.
You need to trim a heck of a lot and pay off the debt.
Trade in your cars for smaller and cheaper used models (but watch out for lease terms).
Cut back on the food bill - shop at Aldi, start buying store brand stuff, meal plan, batch cook, cut way back on alcohol, fruit juice, fresh fruit, branded items, snacks, etc.