UPDATE -- 10:35 a.m. PT, Jan. 28: Klum's rep confirmed the split to Radar, but declined comment.
Supermodel Heidi Klum is back on the market.
A pal close to the pair confirmed the news to People saying, "Martin was there for her during a challenging time in her life and it was something she will always be grateful for."
Klum and ex-hubby Seal divorced in 2012 after seven years of marriage and she started dating Kirsten, 41, shortly after.
"Life is about timing. He was incredibly supportive and they were there for each other, but they're moving on now," the source added.
"They still have a great friendship."
However, Kristen will no longer be employed with Klum as her bodyguard given the nature of their once romantic relationship.