Melissa Etheridge on Friday filed for dissolution of her California domestic partnership with actress Tammy Lynn Michaels, celebrity website TMZ reported.

The women announced their split in April.

In the documents, the Grammy-winning singer cites “irreconcilable differences” and asks for joint custody of the couple's two children, son Miller and daughter Johnnie Rose. Michaels gave birth to the twins in October 2006.

Etheridge,48, shares joint custody of two children – Bailey, 13, and Beckett, 11 – from a previous relationship with Julie Cypher.

The couple exchanged vows in Malibu, California in 2003. They reportedly attempted to marry during the 2008 June-to-November window when gay marriage was legal in California.

Speaking to chat host Oprah Winfrey, Etheridge said her breakup was mutual.

“As mutual as those things can be,” she said on The Oprah Winfrey Show. “It's sad, and we share two children and she will always be in my life.”

“She's a wonderful woman and an incredible mother,” Etheridge added.

Thirty-five-year-old Michaels, however, has suggested the split was not entirely amicable.