Lohan's rep is denying that she had anything to do with the demise of Tony and Stephanie Allen's marriage.

Reportedly Lohan and Dead Stays Alive singer Tony did sex with each other while in rehab in Utah.

Stephanie filed divorce papers last week and kept Lohan's name out the official papers, but said Tony's "conduct and relationship with another woman" basically effed up her marriage. She also attached articles from magazines that bring up her husband's affair with Lindsay.

Lohan's rep toldUs Weekly , “It’s unfortunate Stephanie Allen is blaming the demise of her marriage on Lindsay. Stephanie needs to look at her marriage to determine the reason why things went wrong because it has nothing to do with Lindsay. Lindsay and Tony are friends and that’s all. They are supporting one another through a similar experience. This is a friendship based on trust and mutual support and nothing else.”