Okay... so let's say $7k net. You said:
Family loan - $750
Car Payment - $310 (will be paid off in January)
Mortgage - $1,500
Daycare (monthly) - $1,600
Credit cards - he usually pays around $500 or so on each so, $1,000
Assuming you're paying insurance & taxes in your mortgage payment, right here you're shelling out $5,160/month.
That leaves $1,840/month.
I'm gonna go out on a limb here and say your groceries are running easily $500/month with paper products included and that assumes you never pay more than $3/lb for meat and are not buying entirely organic. Add two REALLY cheap take-outs for the month and you're at $560.
And let's ballpark gas, electric, water, (garbage? sewer?) and cable at another $340/mo (which is way less than I would be paying for all of that).
Those two alone are $900. So $1840-900 = $940 left.
Okay... now maybe cell phones? $100? $840 left.
Target, Walmart and clothing alone could easily eat up $200 of that. $640 left.
Gifts? License renewal? Library fees? Renting a movie? A printer cartridge? Supplies for a school project? Or do you give kids lunch or spending money? That could be $100/month. $540
Of course, ALL HYPOTHETICAL, but you see where this is headed...
You need to know where the money is going since you're helping to spend it and he needs for you to be "in the know" about wth your money sitch is. There's no reason for you not to understand what's going on and there's no reason for him to avoid you knowing.
It's only going to get better when you're both aware of what's going on.