Frankly, the cash envelope system sounds a bit infantile.
A budgeting tool could be a good option, or we just do excel spreadsheets.
First, we worked out what we need for essentials like food or bills paid on a weekly or monthly basis. Then one-off items in the year (e.g. insurance, car service). You need to make sure you're getting the best deals for mortgages, utilities and not overspending on things like children's activities etc.
We pay groceries and bills out of the shared account and have a linked savings account where we transfer money towards the 'once-a-year' stuff.
Otherwise, we have 'pocket money' - same amount goes into our own accounts every month and covers clothes, haircuts, Christmas presents etc. As it's a smaller amount spent on nice things so it's easier to manage.
Everything else gets saved/invested. About every 3 months, DH and I will allocate a couple of hours to review and plan our finances: see if the spending is on track, if any budgets needs adjusting, if it's time to shop around for a new deal or anything + make decisions about allocating money to big-ticket items like holidays, cars, furniture, investments etc.
So basically, a case of watching your pennies day to day and looking after your pounds. If you have a budget, you're disciplined and wait to sit down to agree to any bigger expenses, you'll be a lot less likely to spend money on random shiz.