03/28/2013 at 01:40 PM EDT
Cate Edwards has revealed how she found out her father, John Edwards, had an affair
with Rielle Hunter.
"He told me," the attorney and author, 31, tells Today
in an episode airing Friday, of the former Democratic presidential candidate. "I guess he and my mom decided that that was, you know, how it needed to be done."
As for her reaction, Cate says, "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."
In her book that came out last year
, Hunter wrote of what she called John's many secret lives and the problems he had in his marriage with Elizabeth Edwards, who died in Dec. 2010
The only thing Cate would say on the matter is, "I just thought it was – I thought it was a poor choice, I guess, is all I can say."
But when it comes to speaking about her late mom in general, Cate has plenty to say.
"I miss her in sort of big ways and small ways," she said. "You know, it's big things that go by, like my wedding
. She wasn't able to be there. But we got to talk about it. And I felt incredibly lucky that I got the chance to even have that conversation with her."
Adds Cate, "And I sort of carried out some of her vision which was great to sort of feel her presence there even though she wasn't actually there. And then there are small things. I mean, I get away with bad grammar. I never used to get away with bad grammar."