“He was drinking and flirting with girls,” an insider told the publication. “He was texting Miley while there.”
“He was with all these girls and one was almost fainting, and he kissed her on the lips with no tongue.”
However Simpson has rubbished the report, saying any allegations he cheated on Miley are simply not true.
The seemingly happy couple spent Christmas day Miley's family in Tennessee.
The 27-year-old took to Instagram to share a black and white image of her and Cody around the tree with mum Tish Cyrus, dad Billy Ray Cyrus and siblings Trace, Braison and Brandi.
She captioned the photo with a simple, "Merry Xmas."
Earlier on Miley shared the family's official Christmas pictures with the caption, "Happy Holidays from America's most dysfunctional family."