(FORTUNE Magazine) – Infidelity: Where some see sin, or at the very least a regrettable fact of modern life, Cathy Gallagher, creator of the new Secret Lover Collection cards, sees dollar signs. "This is a market that has been untapped by the greeting card industry," she says brightly. Her $3.99 cards range from Your Sweet Scent to In Too Deep to, simply, Lust. Each comes with its own Gallagher-penned testimonial ("I understand that you are not mine completely and I have to share you ...") and a painterly illustration. In My Weekend Is Over, a couple makes out at a water cooler.

Gallagher says she isn't "for" such dalliances as much as she is "nonjudgmental." But she admits the cards aren't for everyone. "I'm sure Wal-Mart isn't going to carry this card," she says. "We're looking at more boutiquey places and hotel gift shops." Gallagher, who has been married for 15 years, says she has never cheated--and neither has her husband. "At least, as far as I know," she adds. "After all, they are called secret lovers." -- Grainger David