Americans are marrying later or not at all, and more arecohabiting. The median age for first marriages is now 27 for womenand 29 for men, compared with 20 for women and 23 for men in 1960,according to Pew Research. And about a quarter of those who havenever married are living with a partner. Given those stats and thegrowing rate of divorce among those 50 and older, it's importantfor couples to organize their finances and avoid fighting aboutmoney.

In the new book “Loving in theGrown Zone,” Zara D. Green and Alfred A. Edmond, Jr.,co-principals of A2Z Personal Growth Enterprises, list some majormoney-related mistakes unmarried adults in romantic relationshipsshould never make for love. That chapter's title: “Stop FinancialFoolery in the Name of Love.”

Here are seven mistakes for your cohabiting clients toavoid.

1. Don't lend money casually without a writtenagreement that lays out repayment terms. Otherwise you may neverget the money back. You will have no way to prove the funds were aloan, not a gift.

2. Never co-sign a loan. Three out of fourtimes, you, not the borrower, will end up repaying the loan. If youcan't afford it, your credit rating will be tarnished, nottheirs.

3. Don't bust your budget to bankroll a lavishlifestyle for a significant other.

4. Never assume financial responsibility for an adultdependent. Don't pay the mortgage, rent utilities or otherbills of a healthy, able-bodied adult. You have your own financialobligations to meet.

5. Never give your PIN, bank account numbers, ATMpasswords or other personal financial information to alove interest. (I'd add Social Security numbers to the list.) Suchbroad access should be reserved for married couples.

6. Don't assume you can change someone's financialhabits and behaviors, like a shopping addiction, creditcard overuse and frequent late bill payments. “A person who engagedin financial infidelity when you met will not miraculously becometrustworthy,” the book says.

7. Don't be ignorant about your partner's financialhistory. Know it and treat it seriously. “Commingling yourfinances without knowing one another's financial (including credit)histories is like having unprotected sex without knowing oneanother's HIV status,” the book says.

Bottom line: No matter how in love you are,protect yourself at all times.

— Related on ThinkAdvisor:

• The Baby Boomer Bust-Up: Advising 'GrayDivorcees'

• Americans Would Rather Talk About Sex or Death ThanRetirement

• 7 Threats That Can Derail a Client'sRetirement