In filing for dissolution with singer Melissa Etheridge, actress Tammy Lynn Michaels is asking for full custody of their children, celebrity website TMZ reported.

The women announced their split in April.

Michaels wrote on her blog that Etheridge's Friday filing of paperwork to end their California domestic partnership was a shock that left her “blindsided.”

In the documents, Etheridge cites “irreconcilable differences” and asks for joint custody of the couple's twin 3-year-old children, son Miller and daughter Johnnie Rose. The Grammy-winning singer's lawyer is also asking the court to terminate its ability to award partner support.

Michaels, 35, claims she gave up her acting career in 2001 to become a full-time stay-at-home mom for the couple's children. Etheridge, 49, shares joint custody of two children – Bailey Jean, 13, and Beckett, 11 – from a previous relationship with Julie Cypher.

Michaels, who gave birth to the twins in October 2006, says the split left her penniless.

In filing her documents, Michaels also claims “irreconcilable differences” and asks for full custody of the couple's children with visitation rights for Etheridge. She also is asking the court to grant her spousal support.

Michaels filed for a dissolution of marriage. Attorney Steve Knowles told PEOPLE that Michaels' filing was symbolic and that his client would amend the complaint if the court asked.

The women 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.

Etheridge has said her breakup with Michaels was mutual.