"Do girls overanalyze more than us and how does a guy handle that??"

Some girls do, some girls don't. Some guys do, some guys don't. As an individual, you handle it by being honest and accepting.

"What went wrong with these 2 partners??"

You were incompatible. It sounds like the first one didn't want to be officially in a relationship and wanted to keep it to sex - which is what you've stated you wanted, but you didn't seem to want that with her. The second girl TOLD YOU what went wrong - you have incompatable communication styles.

"What could have been done differently??"

Who knows. It's the past. With the second girl you could have tried actually communicating with her - not talking after sex and then saying (to us) that guys can't handle that? Sorry, that's bull****.

"What can I do with the next partner to avoid these situations??"

Be honest and accepting.

"Why do so many girls you meet on dating sites seem to have "problems"??"

I don't think you have a right to judge. You seem to have problems too. Except that maybe more girls feel like being honest about it. And you wouldn't know what most guys are like on those sites because you wouldn't be looking at their profiles.

"If I cannot have luck on dating sites, and girls you meet offline pay
no attention to us or seem to want to do anything besides play with their
Iphone... WHAT IS A SINGLE GUY TO DO??"

Adjust your expectations. Be honest and accepting about your needs and their needs. You clearly don't actually meet them half-way and without compromise nothing will ever work.