Question: Before my son got married, my wife and I told his fiancée’s parents that, in addition to hosting the rehearsal dinner, we’d pay for one-third of the cost of the wedding (we had a general sense of the overall budget). They were very appreciative and agreed to send us an accounting of expenses post-event. Well, we’ve received it, and it looks to us as if they padded the bill. What should we do?

Answer: Be grateful you didn’t offer to pay for half.

Seriously, the first thing to do is everything that discretion allows to determine the actual cost of the event. That means calling all the service providers involved - the caterer, the florist, the band and everyone else - and asking what each of them would charge for a wedding like your son’s. In short, nail down the numbers.

Then if they don’t add up, say to the bride’s parents in your most apologetic voice, “I’m just wondering if there’s been some sort of error. We’d been expecting the wedding to cost around [whatever you believe it actually cost]. Could you double-check the math to be certain there’s been no mistake?” In other words, without being accusatory, give them a face-saving opportunity to adjust the bill.

And if they don’t? While it’s perfectly ethical to challenge any bill you believe to be incorrect, you have another obligation here: to support your son’s marriage. For the sake of family harmony, hold your nose, write the check and keep your suspicions to yourselves. But never agree to share the cost of anything with these people in the future.

Questions? Email Money Magazine’s ethicists – authors of “Isn’t It Their Turn to Pick Up the Check?” (Free Press) – at FlemingandSchwarz@right-thing.net.

Question: I love my wife, but her inability to keep her mouth shut about money has become a real problem. She’s got a couple of relatives whose hands come out whenever they hear that I’ve gotten a raise or that we’ve treated ourselves, for example, to a big screen TV. I handle our finances, and I’m beginning to think I shouldn’t be telling Heather as much about them as I do. Under the circumstances, would this be wrong?

Answer: As any 19th century novelist could tell your wife, a family without secrets is a family without money. It’s too bad Heather hasn’t yet figured out that discretion is a virtue, and for this you have our sympathy.

Unfortunately, the solution you propose – keeping Heather in the dark – while tempting, isn’t kosher. Knowledge is power, which is why spouses have a right to know as much as they want to know about their household’s financial situation. Plus, your plan is impractical: What are you going to do, misrepresent to your wife the cost of every expensive thing you buy or hotel room you stay in?

What needs to change here is not what you’re doing, but what Heather’s doing. She should stop sharing personal financial information with the wrong people. Especially given what you’ve said about her family, her immature behavior is inviting trouble as surely as if she were blowing every paycheck on a high-end hobby or insisting that you invest your savings in penny stocks.

We know, we know: Persuading a spouse to change is easier said than done, and you’ve probably already tried. All we can say is, don’t give up. This is important.

Questions? Email Money Magazine’s ethicists – authors of “Isn’t It Their Turn to Pick Up the Check?” (Free Press) – at FlemingandSchwarz@right-thing.net.