The darker side of Valentine's Day.

As Cheaters Juggle Valentines, Private Eyes Work Overtime; The Feb. 14 'Business Trip'

"It's a good holiday for business," Mr. League says. The Greensboro, N.C., gumshoe has already scheduled five infidelity investigations for Tuesday, and plans to add two part-time sleuths to his staff of four to handle the demand.

WSJ.com ::One Tough Day for Two-Timers