The 27-year-old actor began dating Moore, 42, in May 2003 and suffered a barrage of age gap jokes at the expense of the world's media.
But Kutcher insists he is more than capable of making Moore and her family happy.
He says, "I'm proud to be the husband of Demi Moore and the stepfather of her three wonderful girls. I hope the love that we share can resonate around the world so that someday I can hear its echo.
"Besides, 'boy toy' just never sat well with me."