The Big Bang Theory Season 4 Episode 4 : The Hot Troll Deviation
When the guys run into Howard's ex at the Cheesecake Factory, he ends up confronting his lingering feelings for her. He seeks help from Penny, who agrees on the condition that Howard reveal the reason behind his breakup. He confesses that Bernadette caught him engaging in cybersex with a fellow World of Warcraft player, later revealed to be a male colleague at the university. Howard and Bernadette discuss their relationship at the restaurant and make amends, deciding to give it another try. They go out on a date and are last seen making out in her car.