Lindsay Lohan has been branded a marriage wrecker.
The Mean Girls star - who is currently being treated for drink and drug addiction at Utah's Cirque Lodge rehab centre - allegedly had sex with Tony Allen in a toilet at the clinic.
Stephanie Allen - the mother of Tony's eight-month-old twins Blake and Lakeland - has been left devastated by the claims and has kicked her husband out of their Georgia home.
A friend told the Daily Mirror: "She's had it, period. They tried forever to have kids. She went through IVF three times and suffered two miscarriages, and when they finally got two beautiful babies, he hooks up in rehab with a girl half his age.
"He is trying to live out this rock star fantasy at 40. All Stephanie wanted was for him to be a good husband and father."
Recent reports claim Tony boasted to friends about his affair: "Come on, it's Lindsay Lohan. Hell, yes! Wouldn't you?"
However, 39-year-old Tony - who fronts US band Dead Stays Alive - claims his relationship with Lindsay is purely platonic.
Tony, who recently completed a 45-day stint at the Cirque Lodge, said: "That is against the rules. She is my friend.
"We share a common affliction, and we just talk about life sometimes."
The father-of-two also said Lindsay is set to make a full recovery, saying: "There's no cycle of guilt or shame anymore. She wants to give back to her fans and the people that care about her, and she wants to be able to share her many talents. She's very focused on recovery right now."