The 44-year-old and Tom, 36, ended their marriage in 2013 after seven years, following his confession that he’d been unfaithful while filming in America.
Despite Miranda star Tom claiming he’d cheated just the one time, Tamzin has now suggested there was more to their separation.
The former EastEnders star told The Sun: “I wouldn’t not be with my husband over a one-night stand is all I’ll stay.”
Although she and Tom have had her problems, Tamzin said they make it work for the sake of their two children, Florence, six, and two-year-old Marnie.
She continued: “I will tell them exactly what happened and it will come from me. He’s still their dad and they still have a relationship.”
While she will tell her children everything one day, Tamzin previously insisted they have never seen her upset over the split.
She told Essentials: “There’s never been a time where my children have seen me weeping. We’re all right. We have a brilliant support network around us.
“I do feel like, once you get over everything, we are not that much worse off. Kids adapt, I have a colourful life. It hasn’t gone the way I would have envisaged… It doesn’t mean your kids aren’t happy.”