Anna spent seven months at home after her son, Melvin, was born, and then Henrik, a computer consultant, took over so she could return to work.

Melvin, who has thick brown hair and a pleasant, soft-spoken manner, said he began using the site when his wife left him for another man six months after their wedding.

Luckily for Melvin, what he had wandered into was something a bit more poignant: the woman who had answered his AD was obese and didn't want Melvin to see her body.