@Pemerson,
They are probably right that you will need to find a counsellor on that, because it takes a while to sort through the issues, the behaviours, the ways of thinking, your views on what constitute an attractive man, and probably most importantly for you - how to spot low self esteem in a person, signs of manipulative behaviour, and signs of volatile behaviour.
These men don't 'become' or 'turn' violent - they always had that inside them. The truth is, everyone man can turn violent - but the vast majority have learnt to understand the causes of anger, understand themselves and others, and they have also learnt to cope with anger.....the ones that haven't, are the ones that can turn violent.
A cheap way to help you learn about people quickly in much more depth than usual, is to pick up a few books on handwriting analysis - it is an actual field of psychology, and a huge number of aspects of it prove to be very accurate (just not all aspects). Some of the things it's very good at include telling about emotional stability, and anger issues, despressive tendancies, and controlling natures. It might help