The accusation led to Dima Bayaa, 36, the Syrian star of TV series such as Sabaya, appearing at Dubai Court of Misdemeanours on a charge of issuing insults.
Nesreen Tafesh, 32, also appeared in the first episode of Sabaya.
Taim Hasan, 38, has two children with Dima Bayaa, and they were divorced last year after 10 years of marriage.
In comments published online, Dima Bayaa said Nesreen Tafesh was “the head of the snake” and accused her of being responsible for the break-up of her marriage.
Dima Bayaa said she had taken Nesreen Tafesh into their marital home as a friend, but Nesreen Tafesh had taken advantage of their friendship by having a relationship with her husband.
The actress denied a charge of issuing insults. Nesreen Tafesh was not in court on Wednesday, and the case was adjourned until January 25.
But there was further drama in the courtroom as Dima Bayaa stood before the panel of judges, when police noticed a man raising his phone in a suspicious manner and suspected he might be recording the hearing.
He was taken away but no recordings were found on his phone.