Bret Michaels and Kristi Gibson
07/30/2012 AT 03:45 PM EDT
The bloom is off the rose for Bret Michaels and girlfriend Kristi Gibson.
The "Every Rose Has Its Thorn" singer and his longtime ladylove have called off their engagement, his rep tells PEOPLE.
"Although the couple have separated they remain great friends and are committed to jointly raising their two daughters," says the rep.
Michaels, 49, and Gibson, 41, are parents to Raine Elizabeth, 12, and Jorja Bleu, 7.
After 16-plus years together Michaels finally proposed to Gibson on Dec. 2, 2010, with the cameras rolling; the big moment aired on the finale of his VH1 show Bret Michaels: Life As I Know It.
Gibson stood by Michaels through a variety of ailments over the years, including an emergency appendectomy
, a near-fatal brain hemorrhage
and a stroke