I think the first thing you need to do is be honest with yourself about what you want, because the action you take next will depend on that.
If you have had enough and don't want to risk losing your home, having bailiffs at the door or living later life hand to mouth then you leave - end of. The house will need to be sold and you will get some money (if there is any equity) to get yourself set up elsewhere.
If you still love him and want to stay together IF he will changes, then you need to lay it out to him but you need to decide what you will do if he refuses - are you prepared to leave him? If you threaten it you will need to mean it.
For example you could suggest that he agrees to this, otherwise you will leave:
You sit down together and look at all of your incomings and outgoings (including his debt) and see what it looks like. If you are confident enough you can probably work out what you need to do and seek help from online forums (debt-free wannabe on the MSE website is excellent for helping people figure out how to get out of debt).
If you are not confident enough, or the debt is so unworkable that you can't cover it with your incomings you will need to seek advice - but be aware, with a mortgage you cannot get a debt relief order. You may however be able to get an IVA which will protect your house - but these do have implications, so please make sure you seek independent advice first.
You need to suggest that he gives you joint control of the finances - a joint account for essential bills (including clothing, kids needs etc), joint savings accounts for things like christmas and holidays, so you can monitor and make sure that the essentials are being paid for.
If you are lucky enough to have enough left in the budget for some 'fun' money, that gets kept by you both separately but only after the bills are paid.
It is up to you whether all of your income goes into one pot and then leftover after bills separated into individual accounts, or whether you work out the amount and set up the standing order to transfer the right amount - personally I would suggest the former with set amounts of personal 'pocket money' with the rest going towards bills / household savings, so that any emergencies are covered.