Elaine Irwin and John Mellencamp
08/15/2011 AT 01:10 PM EDT
Rocker John Mellencamp and his estranged wife
, model Elaine Irwin Mellencamp, are officially divorced.
The couple, who were wed for 18 years and have two sons – Hud, 17, and Speck, 16 – separated on Sept. 1, 2010, and he filed for divorce
on Jan. 14. Their divorce, his third, was formalized on Aug. 12.
The couple negotiated "an amicable settlement of all issues involving property and maintenance rights, the custody and support of their children, and all other issues," according the settlement agreement.
They will share joint legal custody of the boys, with their mother – who will return to the name Elaine Irwin – having primary physical custody. John will pay child support and for their schooling. No other specifics of their 31-page confidential final settlement agreement were made public.
In court papers, Mellencamp said the marriage was "irretrievably broken." Indiana is a "no-fault" state, meaning a couple can divorce for almost any reason.
The Mellencamps lived in a 56-acre estate in Lake Monroe, Ind., which is close to Bloomington. Both had said they planned to stay in Indiana, where "they will continue to raise their children," his rep said in January.
Since the split, John Mellencamp, 59, has been dating Meg Ryan
, and the pair have been spotted around Martha's Vineyard, New York City
In addition to the two boys with Irwin, Mellencamp has three other children.