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Whether you're roommates or lovers, there's no one right way to divvy up living expenses. You need to hear that, because a lot of people will tell you otherwise.

They'll insist everything should be split 50-50 or that couples should combine all aspects of their finances, or that expenses should be split proportionate to income.

The One Right Way folks live in a black-and-white world. Out here in the Technicolor universe, there are all kinds of complications. Here are just a few situations my readers have reported:

  • You're roommates, and you've agreed to split expenses evenly. But one of your roommates works at home and keeps the heat blasting all day, driving up the utility bills. And since he's around all the time, he's eating more of the jointly purchased food.
  • You've moved in with your honey and agreed to split expenses proportionate to your income. But now you're out of work, and your honey is chafing at having to pay most of the bills.
  • Same situation, but you agreed on a 50-50 split. Your beloved has tons of disposable income, and you're going in the hole every month. Resentments ensue.
  • You're married and agreed to share and share alike. But you're constantly arguing about how much is spent at the grocery store, whether to cut the cable bill and if it's time to replace your aging appliances. The person who's making less feels he or she has less power in the relationship, which exacerbates the tension.
  • You're married and are contributing to a household expense account in proportion to your incomes. But one of the expenses paid out of that account is an obligation occurred before you got together -- your spouse's child support, for example, or credit card debt. The idea that you have less of your hard-earned money to spend because of this is starting to eat at you.

The one thing these expense-sharing scenarios have in common: They're not working. If you're living with an expense-sharing scheme that's causing problems, it's time to re-examine your assumptions and your approach.

Liz Weston

Liz Weston

You might just need to reframe the problem. Instead of focusing on expenses and income, for example, you could focus on what's left over.

"After trying every imaginable way, finally what's worked for our decades-old marriage is a residual method," one of my Facebook fans wrote when I asked how joint expenses are managed. "Each party deposits enough into (the household account) so that both are left with an equal amount of disposable income. So regardless of the income, both are left feeling squeezed or flush in equal measure. And no one is secretly envious of the other's higher (or) lower contribution."

Whether you need to try a whole new method or just tweak the one you have, here's what you should keep in mind:

If one of you has a problem, everybody has a problem.

Resentments tend to spill over and spoil relationships.

"There's nothing worse than not being happy with the financial situation when you're living under the same roof," said Annamarie Pluhar, the author of "Sharing Housing: A Guidebook for Finding and Keeping Good Housemates." "You're in a community with other people. You want to live a life that feels good with and about each other."

Assuming all parties are rational and reasonable, you should be able to work out an arrangement that everyone agrees is fair -- as long as everybody is willing to compromise. (If someone isn't rational and reasonable, the bigger question is: Should you be living with this nut case?)

Don't be that person. You know the one: the person who whips out the calculator at the restaurant and starts figuring everybody's share based on what each one ate and drank. "OK, you had the premium beer, and I had the tap water, so you should pay $5.25 more, plus a 15% tip on that amount . . ."

Life's too short to demand proper accounting for every dollar spent. You don't want to be a doormat, but a little flexibility and generosity can go a long way in preserving relationships, Pluhar said.

But do track your expenses. That said, it's hard to come up with a fair arrangement if you don't really know what you spend. If you're moving into a new place together, you'll have to estimate the various expenses (shelter, utilities, food, etc.). Even if someone is moving into an existing situation, expenses can change after he or she arrives.

Tracking expenses for a month or so should give you a good baseline from which to craft a cost-sharing plan. How you go about dividing those expenses will depend on your relationships and your financial situation, but it's best to work out some kind of agreement before you move in, especially with roommates.

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"The primary reason to have roommates is because it's economically advantageous," Pluhar said. "Everything needs to be clear and agreed on in advance."