The news of South Carolina Governor Mark Sanford's affair shocked the country, but his wife Jenny Sanford reveals that she knew about the transgressions six months prior to her husband's press conference. With 20 years of marriage under her belt and four sons, she tells Rachael that she tried her best to save all that she and Mark had achieved together. "I'm a big believer in marriage and family, and so I had been trying very hard to reconcile and to keep him from going back to see his mistress, but clearly it didn't work," Jenny relates. "When God gives you four kids, I think it's incumbent upon you to do your best and to see if you can stay together for the sake of that family. And I loved him! I married him because I loved him."

Rachael asks Jenny if there was a specific turning point that made her finally decide to leave the marriage. "I think the dissolution and the breakdown of a 20-year marriage isn't something that happens very flippantly. I think you have to be very prayerful and careful," she says. "To me, it has been more of a process. Our marriage actually withstood a lot of challenges. This is a quirky guy! I found him very refreshing and wholesome, but he beats to a different drummer and I knew that from the beginning. Yet somehow through it all he stayed true to his political principles, but he lost sight of the values that were the core of our marriage, and those matter more to me."

Though Jenny has forgiven her husband, she explains that it's hard for her children to understand the difference between forgiveness and reconciliation. "They're a little confused if Mark shows up and we get along beautifully," she says. "We both made the commitment that we're going to keep raising them peacefully and in a compatible matter. And yet that even confuses them a little; [they say], 'If you're getting along, why don't you stay together?' I say, 'Because we want to raise you guys together and we want to get along. I still love him, I just can't be married to him.'"

There have been a lot of questions raised about Jenny's decision to marry Mark in the first place, given the revelation that he removed the promise to be faithful from their wedding vows. "That could have been a flag!" Rachael remarks. Watch the video above to hear Jenny share her reaction to her husband's request, and why she decided to go through with the wedding anyway.

Web exclusive! Read an excerpt from Staying True, which Jenny sums up, "I talk a lot about my faith and I talk a lot about the importance of relationships with your family and your good friends because they help you stay accountable; when you start to drift they're the ones who say, wake up!"