Spencer Pratt and Heidi Montag have at least one more thing to argue about. The soon-to-be-divorced couple is squabbling over Pratt’s future plans to pen a tell-all book about his private life with Heidi Montag.

“This is exactly why I left him,” Montag told reporters when asked about the book. “Right now, I’m looking into my legal options.”

In an interview with Us Weekly, Spencer Pratt said his book will detail his entire relationship with Heidi. The tell-all will also contain details about Montag’s family life, particularly her relationship with her mother Darlene Egelhoff.

Spencer Pratt and Heidi Montag will be divorced on Valentine’s Day 2011. Heidi formally filed for divorce on the couple’s first wedding anniversary.