Edwards' daughter says she was 'devastated' over affair

The eldest daughter of John Edwards, speaking out about her father's affair and the fallout from it, said in an interview set to air Friday that she was "devastated" and "disappointed" when she found out about the infidelity. 

Cate Edwards, speaking with NBC News, said her dad was the one who told her about the affair. 

"I guess he and my mom decided that that was, you know, how it needed to be done," she said. "So yeah, I was devastated. And I was disappointed. I mean, these are my parents. I had grown up with a lot of love in my family. And it was hard to see them go through this." 

Asked if she was mad, the 31-year-old attorney said "of course." 

Edwards' father -- a former senator, vice presidential nominee and presidential candidate -- confessed to the affair with Rielle Hunter after dropping out of the 2008 presidential race. He eventually admitted to fathering a child with Hunter, though he had denied paternity for months. 

Edwards was later indicted on campaign finance charges, but last year walked after a mistrial was declared on all but one count, on which he was found not guilty.  Elizabeth Edwards, his late wife, died in 2010. 

The interview with Cate Edwards is set to air Friday on TODAY and "Rock Center with Brian Williams."