The Boyzone singer - who yesterday announced he and his spouse Yvonne were separating after 12 years of marriage - was reportedly kicked out the family home on17.05.10 following a furious row where he admitted to being unfaithful to her during his recent solo tour.
A source told the Daily Mirror newspaper: "Yvonne was heartbroken but she made her mind up on the spot. The cracks were there already, but this was the final straw. She isn`t the sort of person to forgive and forget. Ronan has accepted her decision."
Ronan and the former model - who married in 1998 - have known each other since they were youngsters and have three children, Jack, 11, Marie, nine, and Ali, four, together.
It has been reported the hunky pop star was unfaithful with a backing dancer - rumoured to be pretty blonde Francine Cornell - who is now in discussions to sell her story.
Friends of the couple were shocked by the news of their split.
One pal told the Daily Star newspaper: "It is hard for the wife of any pop star when they go off on tour. The separation can take its toll on relationships. Situations that normally would not arise can get out of proportion. We hope Ronan and Yvonne can get through this."
Boyzone manager Louis Walsh - who has known the pop star since his career began in 1993 - was also stunned by the news.
He said: "I didn`t see it coming at all. Ronan and Yvonne have always been very close. They were a great couple and spent their time together. It`s come as a total surprise to everyone."
The pair apparently had blazing rows on 18.05.10 and discussed their separation with their young children before Ronan was spotted being driven away from the family home in tears yesterday.
The pair are "devastated" about their separation and are waiting for the situation to calm down before they discuss custody arrangements and divorce.
A source told The Sun newspaper: "Telling the kids was heartbreaking. They were both just devastated and never thought it would happen. Custody and things like that have not been talked about yet, it`s just too raw."