Two nudists walk into a therapist's office...
No, it's not the beginning of a bad joke - it's a British ad for Comfort fabric softener (hat tip to AdFreak).
In the spot, a nudist's wife cheats on her husband with another man. But it's a slightly different type of infidelity: the male nudist catches his wife, "sniffing, touching, fully clothed" with another man. "You disgust me," the husband cries.