Tiger Woods cheated on Lindsey Vonn

US skier Lindsey Vonn reacts as she is asked about her relationship with golfer Tiger Woods during a news conference in Seoul, May 6, 2015. Vonn was named honorary ambassador for the 2018 PyeongChang Winter Games. [Photo/Agencies]

It's been more than a week since Lindsey Vonn revealed she and pro-golfer Tiger Woods called it quits.

And it has since been alleged that their three-year relationship came to an end because he cheated — again!

"He had a relapse in the sex department," a close friend of the 39-year-old golfer tells the Daily Mail. "Lindsey found out about women again. [He] always [cheats] while he's on the road. Just like when he was with Elin."

Five years after tying the knot, his marriage to model Elin Nordegren came to an end in November 2009 when it was revealed the pro golfer was having several extramarital affairs.

The friend claims Tiger "can't help himself," and doesn't see sleeping with a stranger as an affair. The pal alleges, "Knowing Tiger, he doesn't even see it as cheating because there's no romance or feeling there. It's just a stress reliever, like a high-ball or two after a bad day."

Additionally, the friend says the father-of-two decided to come clean to Lindsey, 30, about his "one-time slip" — something he never did with Elin — but even so, it was enough for the pro skier to end things.

"After nearly three years together, Tiger and I have mutually decided to end our relationship," the Olympian wrote on Facebook on May 3.

"I will always cherish the memories that we've created together. Unfortunately, we both lead incredibly hectic lives that force us to spend a majority of our time apart. I will always admire and respect Tiger. He and his beautiful family will always hold a special place in my heart."