The admitted past marital infidelities of Mexican presidential front-runner Enrique Peña Nieto have become fodder for a new ad campaign by an agency that arranges affairs for married clients.

A billboard bearing Peña Nieto's picture and the text "Unfaithful to his family. Faithful and committed to his country" appeared this week in Mexico City.

The ad was commissioned by the Mexican unit of Ashley Madison, which describes itself as "the world's leading married dating service for discreet encounters."

"What we offer is that if you have an extramarital relationship through us, you won't be caught, and so those people should use our (Web) page to do it secretly," the president of Ashley Madison Mexico, Ricardo Castañeda, told Efe.

Peña Nieto's dalliances didn't stay secret, as he fathered two children with two different mistresses while married to his first wife, the late Monica Pretellini.

The photogenic politician has publicly acknowledged those affairs, but now presents himself as a model husband to soap opera actress Angelica Rivera.

With less than a month to go before the July 1 election, Ashley Madison decided the time was ripe for the ad featuring Peña Nieto, Castañeda said.

"He is leading the polls and it was very easy to do it," the executive said. EFE