Not necessarily a mother complex, my theory is that these type of men often have to deal with stress and pressure in their work life day to day, so to come home to someone that rules them and takes the responsibility off them is a pleasure.
That's why many of the men that enjoy being with a strong woman are often boardroom directors and hold other high positions in society.
As they say, whenever you see a successful man, you'll find a strong woman by his side.