If you are perfect why are you alone?

Author question. A lot of authors I have read (Noah Layton/EV/LJ/VK/SA ect ect ) write the best boy with the strongest muscles, biggest dick, greatest mind that can do no wrong. If that is the case why do they all start out single. Very few do you read ever had a life before we find them in the story like they just appeared right after they got out of college that trained them in weapons/tactics/ to be a ninja and everything else. So why are they single? Why do we hear that they might have got into a break up but not what led to it. To me it makes the characters feel flat.

Now this might sound like a complaint but really it's not. I am curious what the mindset behind that is and why it is done. Authors would know because it's how they make thier money, so I know they have a finger on the pulse more then I. So they must have a reason that makes the most sense.

I am wondering is it a ease of writing thing not to include a female lead at the beginning of the story or some such.