Who initiates getting back together more; men or women ?

It doesnt matter who initiates it. Once you split up your chances of making ít are practically zilch. Better just to move on.

Likely it's the men. And likely because they are more aggressive.

Why is it few women actually PM men on sites like this?

Oh there are a few. Yet it's mostly men that initiate PMs.

I think both equally it's usually the one with lower self esteem.

Men i would guess as they usually are why they broke up

Men. They always want you back.

Men