The former glamour model's marriage to the 28-year-old builder was rocked when he admitted to cheating on her with two of her best friends but Katie insists he has ''changed''.
She said: ''Other people think Kieran is a cheat and a liar, but I don't care what they think. I'm the harshest judge and I know how much he has changed. In the past two years he's gone from a boy to a man. I trust him 100 per cent.
''He's not vain - he hardly looks at himself in the mirror. He's even got a little pot belly, which I actually like a lot. His whole life revolves around me and the kids. We never row, we have a laugh, and he's the one man who makes me totally happy.''
And the 37-year-old television personality insists she ''learnt a lesson'' from his betrayal.
She added to The Sun newspaper's Fabulous magazine: ''When he cheated on me, everyone told me to get rid of him. It would have been easy to do. But there was something in me that knew I shouldn't give up on him, and I've learnt a lesson about myself because I've never before been good about second chances.
''What I'd say to any other woman who goes through what I went through is if you think there is something worth fighting for, fight for it. Don't throw it away.
''Despite all the pain and all the horribleness that was going on when I found out he'd cheated, I knew in my gut he was still the right man. And he's a better man for having gone through therapy and all that. I love him to bits and so do my kids.''
'Smalls Change (Meditations Upon Ageing)' arrives in April.
The two awards have made for a great 72nd birthday present for the country music icon.