Ruth Houston, the author of "Is He Cheating On You? 829 Telltale Signs", says the following nine behaviors may be indicators of a spouse's infidelity:

• Credit card statements that reflect charges for flowers, jewelry or other gift items that the spouse did not receive;
• Unauthorized or surprise withdrawals from joint bank accounts;
• Deposit slips or bank statements that indicate the existence of a previously unknown checking or savings account in the wife's/husband's name only;
• The liquidation of assets (stocks and bonds, stamp or coin collections, artwork, etc.) without a plausible explanation;
• Misrepresentation of or failure to mention raises, bonuses or overtime pay;
• Income tax returns that reveal unexplained or previously unknown travel-related deductions;
• Financial records (canceled checks, receipts, money orders or other documents) that indicate a spouse has been paying someone else's bills;
• A sudden decrease in disposable income;
• An increase in ATM withdrawals.