The couple married in 2010 but have been separated since January 2013. Duff, 27, had been open about wanting to try and make their marriage work and the Younger star has been photographed often with Comrie, 34, over the past two years.
But according to sources, Duff had enough after Comrie was spotted drunkenly propositioning women at a restaurant in Beverly Hills, Calif. One eyewitness claims Comrie pulled out his wallet at one point and asked a woman, who was on a date: "How much for sex? Name your price."
In Duff's filing she cited irreconcilable differences and requests primary physical custody of their son Luca, who turns three next month.