I think people mistake "coming back". If a guy you used to date/mess around with contacts you out of the blue months or years later just to say Hi, or to see if you're available for a quickie (LOL), it's not really coming back in the sense most are looking for. Sure there are times when a guy realizes what he lost and tries to reappear (I had it happen once but oddly enough before readings)...but it's rare.
The majority are jerks just reaching out because they are bored, want to get laid etc. I'm speaking for men, mostly. they are really simple creatures at the end of the day and don't put all the emotional thought into these things that women do.