It wasn't guilt or the looming threat of the story coming out that made Arnold Schwarzenegger spill the beans about his affair to wife, Maria Shriver -- it was Shriver's intuition.

The former first lady of California had longstanding suspicions about the identity of Mildred Baena's son's father. According to a joint investigation by RadarOnline and Star, she finally asked the housekeeper, who had been working for the family for 20 years, if Schwarzenegger was her now-13-year-old son's father. Baena broke down and confessed. The website reports that Schwarzenegger only admitted it after Shriver confronted him.

"Maria has suspected this for a long time and she asked the housekeeper," a source told RadarOnline. With confirmation from Baena, "Maria then went to Arnold and he confessed."