Even in the best of times, money can be a conversational third rail in a relationship. Most couples, whether married, engaged, or cohabitating, cop to having an occasional tiff about the family finances.

Shocking, I know.

If you want your union (financial and otherwise) to last, it's time to do something radical: Set some ground rules to prevent your next money fight. "Rules" may sound overly formal -- however, couples report that rules are the very thing that keep their money talks from devolving into bicker-fests.

If your money melees typically result in one of you sleeping on the couch, rest easy. These five simple strategies can strengthen your financial union, starting today.

Five ways not to fight
To steer tough interactions toward more fruitful results, heed the advice of negotiation experts (the folks who coach executives, family mediators, political leaders, and yes, hostage negotiators). The latest thinking in the field is that the key to a successful negotiation is not to win, but to reach an agreement that meets everyone's interests. That's certainly sound advice for twosomes who have to share the same tube of toothpaste every night.

Here's how to keep the financial peace in your household:

1. Preempt the conflict. The best time to initiate problem-solving is before any emotional flare-ups can steer the conversation off course.

2. Approach problems like partners, not adversaries. Since your long-term relationship is critical, foster respect and trust for future interactions. The goal is not to defeat the other person -- it's to come to a resolution together.

3. Focus on what really matters. Don't turn every money issue into a formal summit. Acknowledge and appreciate your partner's biggest and most sensitive financial concerns and communicate yours as well.

4. Set up money rules that encourage autonomy. Reduce the number of potentially contentious interactions by establishing clear decision-making guidelines. When I interviewed Daniel Shapiro, one of the authors (along with Roger Fisher) of Beyond Reason: Using Emotions as You Negotiate, he suggested a three-bucket sorting system for making money decisions:

  • Inform: I make the decision myself, and then I inform you.
  • Consult: I get your input, and then I make the decision myself.
  • Negotiate: Together, we negotiate a joint agreement.

Come up with dollar- or decision-based parameters for each bucket. When in doubt, Shapiro suggests using the "ACBD" rule: "Always consult before deciding," which can help you avoid having to sleep on the pull-out couch in the den.

5. Prepare a relationship first-aid kit. Don't let your money conversations get sidelined by negative emotions. If things get heated, take a break. Pre-arrange a collection of your favorite couple-y things (e.g., cards you gave each other, vacation pictures, movie passes to get you out of the house). Kiss and make up and refer back to tip No. 1.

Finally, a "get out of jail free" card
If you have to pour your heart into cultivating just one relationship building block, many pros agree that "appreciation" is the one to address. "We all want to feel appreciated within business, within marriage, within any relationship; empirically, the research has shown it to be true as well," Shapiro says.

Appreciation in a relationship context doesn't mean "approval" or "gratitude" -- it's about understanding, respecting, and acknowledging the other person's point of view. Even if you don't agree with how they see things, their viewpoint has merit because, quite simply, it's how they feel.

Just like there's no "I" in team, there's no "me" in "we." Are you cool with that? (A rhetorical question, by the way.) Good. Now you'll have to find something besides money to bicker about -- perhaps leaving dirty dishes on the coffee table, or forgetting to pick up the dry cleaning.

For more on navigating financial issues with your sweetheart, see: