India, March 25 -- Maria Shriver is opening up on her "brutal" divorce from Arnold Schwarzenegger. In her new book, I Am Maria, the 69-year-old detailed how her ex-husband's infidelity that led to their separation left her emotionally broken.

"It broke my heart, it broke my spirit, it broke what was left of me," Shriver wrote in an excerpt of the book obtained by People. The former First Lady of California ended her 25-year marriage with the Terminator star in 2011 after he admitted to fathering a child with housekeeper Mildred Baena.

Schwarzenegger secretly welcomed his son Joseph Baena from Mildred in October 1997. After the news went public, Shriver filed for divorce, ending their decades-long marriage. "Without my marriage, my paren...