you asked for signs...
a remarkable sign that most people miss, or disregard, is their account of their exes. If every ex did him/her wrong (I am going to use the pronoun HE for the abuser from this point on...but as was already said, SHE can be the abuser as well), was a dog; screwed everyone; ran to someone else; didnt take care of the house, the kids; was mouthy and disrespected him in front of his family and friends; etc....if the exes were ALWAYS the problem, we have transference going on here.
There is relatively new theory of transference called AMT...Abusive Multiple Transference, where the abuser not only transfer negative feelings of their abuser to their victims, but also transfers the power and dominance of their own abuser to themselves.*
In simple-ese?
... if the abuser felt they were always shit on, they will always believe they will get shit on, and they themselves will also always shit on others....
(*I found a really good explaination of transference and projection that relates it to domestic violence!
http://wiki.answers.com/Q/What_is_tr...ection#slide72)