The Other Side of the Bed(2002)

Original title: El otro lado de la cama

When Paula leaves her mate Pedro, he misses her and looks for comfort with his best friends, Javier and Sonia. Paula is having an affair with Javier. Pedro tries to find who is the secret lover of Paula, and hires a private eye. Meanwhile, while comforting Pedro, Sonia has a one night stand with him and Javier thinks she is cheating on him with her lesbian friend Luzia.