The 'What Happens in Vegas' star - who has been married to mother-of-three Demi for nearly three years - hadn't thought about the decision properly when he tied the knot with Demi, who is 15 years his senior.
Ashton, 30, said: "Sometimes the most illogical decisions you make in your life can be the best ones when it comes to love. In a lot of cases, when you think about things too much you make the wrong decisions.
When I married Demi, I was 25, I was the host of 'Saturday Night Live,' I had the number one show in America, I had the number one show on cable and the number one show on FOX, and I'd just beat Prince William as the most eligible bachelor in the world.
If I thought logically, my logical mind would have talked me out marrying a woman with three kids, an ex-husband and a whole different life - but I let my illogical mind and heart talk me into it."
However, Ashton insists marrying Demi, now 45, was one of the best decisions of his life.
He added: "But this morning I woke up and finally my logical mind caught up to my heart and I know marrying Demi was the smartest decision I've ever made."
Demi has three daughters with ex-husband Bruce Willis, with who she is still close friends.
©2008 AOL Australia Pty Limited in association with Bang Showbiz. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
Related Article: Ashton Kutcher Refuses to 'punk' His Movie Co-Stars
