Getting divorced can be like taking a crash course in emergency finances – one you have to take whether you want to or not. And when kids are part of the mix, and you’re a newly single mom – you need to master that class right away.

The first lesson – and one of the hardest to swallow – is this: Just because it’s written into your divorce agreement doesn’t mean it will actually happen. I’ve seen many cases where women – including me – counted on the financial arrangements laid out in their divorce settlements only to end up scrambling when their exes didn’t come through. The takeaway from that lesson is to never count on money from your ex, no matter how sincere or reliable they’ve been in the past.

That said, it’s still really important to clearly document the financial responsibilities. To do that, you need to be realistic about the finances pre- and post-divorce, and that means starting with a complete financial picture. You can only really split things fairly if you know what’s there to split, so dig everywhere you can think of – and then dig more.

Once all of the financial cards are on the table, follow these golden rules to avoid future disasters that could ruin your financial foundation and future.

Cut all of your financial ties: If you keep even a toe in your ex’s financial waters, you could be on the hook if their financial situation goes south. So pull the plug on all of your joint finances – everything from bank accounts to credit cards to car titles – to protect your future finances.

Take the cash: Any time you have a choice between cash right now and something else, take the cash. For example, if the other side offers $150,000 in pension payouts starting 15 years from now or $100,000 cash today, take the cash. If your ex offers you a choice of $1,000 a month for the next 5 years or $50,000 right now, take the right-now cash. Yes, you technically get less money, but that’s hypothetical money. Cash in hand is real cash.

Know your tax situation: Your divorce creates all kinds of potential tax pitfalls, from who’s claiming the kids to getting hit with an unexpected tax bill when you sell your house. While your divorce is ongoing, you need know how taxes are being filed (joint or separate) how any joint refunds will be split, and who’s responsible to pay the bill if you owe.  Make sure you pay attention to these tax issues as assets get sold and tax returns get filed…because the IRS definitely is.

Plan for Less Money: No matter what your finances looked like before the divorce, you’ll have less money now. On top of the cash drain of legal fees (even the least expensive divorces cost money), your family economics are changing and money will be tighter, especially in the beginning when you’re getting used to all the changes. Resist the urge to splurge – especially on your kids. Be prepared for legal delays (which could delay alimony and child support payments) and surprise debts (like a high balance on a joint credit card). By keeping a tight lid on spending now, you’ll be in a better financial position to move forward.

Don’t rely on support payments: No matter how trustworthy your ex has been, no matter how steady and reliable, do not rely on support payments. Accept them, use them, absolutely, but don’t count on them to meet your regular monthly expenses. Situations change. Your ex could be in accident, lose their job, be late with payments, or just stop paying. If you need that money to pay your bills, you will be in financial trouble if that money is late or gone. Keep your spending to what you earn on your own, and you’ll never have to panic when the check doesn’t come.

By taking these preventive steps, you’re protecting your financial future. And when you’re flying solo as a single mom, that protection is crucial.