if he were a good man,of course,i hope that we could be friends,and i will treat him as before .Otherwise,i wont .

It is best no to. Just move on and make new friends.

Whether keep in touch as before depends on the condition.If she is a nice person and I still love her, I will give myself a chance.First,I will be her friend again and then find a better way to present myself and to show my love in order to make her re-consider me to be her boyfriend.Otherwise, I'll let her go and avoid to keep in touch with her.

It depends on why you broke up in the first place. If someone cheats on you then it will be very hard to trust him/her again.

I think no problem to keep in touch as before. because he had been a part of our lives. communicate properly friend or relative I think it's better.