EXCLUSIVE

Sarah Palin's oldest son has pulled the trigger on his marriage by filing for divorce ... TMZ has learned.

Track Palin and his wife, Britta, jointly filed divorce docs in an Alaskan court.  Under Alaska law, by filing together, they are signaling they have fully settled property and custody issues, including child support.

As for custody, the now ex-couple has a 1-year-old daughter, Kyla.  One interesting point ... the agreement says Track and Britta must watch a 48-minute video showing them how to explain the breakup of the family to the child.

Track and Britta married in May, 2011. 

Track is an Army reservist and served time in Iraq.  He's a commercial fisherman and plans to go back to college.

EXCLUSIVE

Sarah Palin's oldest son has pulled the trigger on his marriage by filing for divorce ... TMZ has learned.

Track Palin and his wife, Britta, jointly filed divorce docs in an Alaskan court.  Under Alaska law, by filing together, they are signaling they have fully settled property and custody issues, including child support.

As for custody, the now ex-couple has a 1-year-old daughter, Kyla.  One interesting point ... the agreement says Track and Britta must watch a 48-minute video showing them how to explain the breakup of the family to the child.

Track and Britta married in May, 2011. 

Track is an Army reservist and served time in Iraq.  He's a commercial fisherman and plans to go back to college.