In a PEOPLE's excerpt from her upcoming memoir, I Am Maria, Maria Shriver reflected on her divorce from Arnold Schwarzenegger, opening up about the "brutal" split from her husband of 25 years following the revelation of his affair.

Maria Shriver detailed her emotional breakdown in a hotel room after learning of Arnold Schwarzenegger's affair with their family's housekeeper Mildred Baena, who gave birth to Joseph Baena.

Maria Shriver is opening up about loss and grief in a big way. In her new book I Am Maria - a collection of poems and reflections by the author - Shriver, 69, revealed she was unable to get off the floor of her hotel room after learning of her husband Arnold Schwarzenegger's infidelity.