Heidi Klum and Seal realised their marriage was over during their trip to Aspen over the holidays, it is claimed.

The couple announced on Monday that their almost seven-year marriage was over, but People magazine reports that their skiing trip over the holidays was the "final straw".

The parents-of-four both have busy schedules and were hoping that coming together in the Colorado resort town would be great quality time for them but it wasn't to be.

"Aspen didn't go as well as planned there were more lows than highs," a source told the publication. "Aspen was the final straw."

"When they came together for Christmas as a family, things had changed and they fought a lot," another insider said.

"Their Aspen trip was a bit of a mess. Instead of enjoying being back together as a family, it was difficult for them to get along."

Heidi was said to be "done with the arguing" and made the decision that was best for their children.

"She doesn't want to fight anymore and thinks it's better to separate before their arguing starts to affect their kids," the source added.

But one photographer who was in Aspen said that Heidi, 38, and Seal, 48, showed little sign that their relationship was in trouble.

"They seemed very happy together," the snapper said. "They couldn't stop kissing and cuddling. They spent a lot of time with their kids, but also managed to sneak in several solo ski runs together.

"If they were having problems, they were definitely not showing during the day."