According to the petition 48-year-old Dina filed in Monterey County Superior Court on Monday, she is seeking spousal support. The document also reveals the couple had a premarital agreement.
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The pair's break up was originally announced in August. The four times Oscar-winning actor is said to remain close to his wife, but the two have been living apart for quite some time – they have not been pictured publicly together since 2011 and, according to a source, the two actually split in June 2012.
"Clint fell out of love with Dina a long time ago," a source told Us Weekly, noting that the separation was "amicable".
Last year Dina stepped into the spotlight when she invited cameras into the family home for her own reality show, Mrs Eastwood & Company, which also starred the couple's daughter Morgan and Francesca, 19, Clint's daughter from a previous relationship.
The show – which ran for one season in 2012 – followed the lives of the Eastwoods in Carmel-by-the-Sea, California, where Clint, 83, was mayor from 1986 to 1988.
The twice-married Million Dollar Baby actor wed first wife Maggie Johnson in 1953, half a year after they met on a blind date. The couple had a daughter, Alison, and a son, Kyle. Clint has five more children from other relationships.