There are two parts to your question from above. One is related to spousal abuse and the other is sexual abuse. I think they can both be understood the same way. Patrick Carnes writes about sexual addiction. I think we can extend his explanation to both verbal and physical abuse of another.
Addictions are compulsive, and involve no deep seated motivations in the subconscious.
What this means is simply that verbal abuse, physical abuse, and various abnormal sexual acts make the perpetrator feel better. It is only a little different from drug addiction or alcoholism. They get relief from the internal tension they feel in much the same way as the gambler gets relief from gambling or the shopper gets relief from shopping.