A massive 731,000 fans watched the programme on RTE on Tuesday to see the latest development in the drama.
And around 46pc of the available audience watched to see if Suzanne and Damien's marriage would survive the domestic abuse.
The ratings have been rising since the storyline began in September.
Viewers saw Damien being rescued from Suzanne on Sunday, while tonight Suzanne's sister Yvonne returns to the show.
Yvonne gets angry when Suzanne tells her Damien had an affair with Neasa.
She rushes out to the beer garden and tells Neasa she is a slut and needs to move out, according to show insiders.
And Yvonne causes another scene when she sees Damien coming into the bar.
The domestic abuse storyline has made such an impression that it led to a significant rise in calls to a national support group for male victims.
The script has touched a nerve with many men who are suffering similar attacks at home.
The scenes aired on the series have resulted in a rise in calls to national helpline and support service Amen.
The support service said the number of callers had increased dramatically as a result of the Fair City plot.
"Many factors have contributed to this, and Fair City is one of them," said Niamh Farrell, manager of Amen, recently,
The show featured Suzanne, played by Sarah Flood, beating her husband Damien for cheating on her.
Viewers have seen Suzanne engage in abusive outbursts and acts of physical violence towards Damien -- played by Maclean Burke.
RTE said the storyline was in the making over an 18-month period and involved extensive liaison with and support from key bodies in the area.