For three-and-a-half years Catherine Garrod was in a relationship with a "charming and attentive" man who was "great at writing cards" with "heartfelt" messages.
Then his other girlfriend got in touch.
According to Metro.co.uk, Garrod received a message on Facebook one day from a woman who thought Garrod was having an affair with her partner.
"When she found me she assumed I was the affair," Garrod said. "But when she went through my Facebook profile she realised we had been together for a long time."
As they talked, they realised they'd not just been led to believe they were both the man's one and only, they also discovered they'd been gifted the same "heartfelt" letter among many.