I don't think you can define abuse as one-sided. The abuser always thinks that the other person has said or done something that triggers the abuser's response; and, in fact, there usually IS something that the victim has said or done that acts like a lightening rod. Perhaps a better definition incorporates the concept of over-reaction, a reaction that is disproportionately inappropriate.

Anyway, during my life I have sometimes/often felt that it would have been easier to have been physically beaten rather than to take the relentless comments, the mean-spirited hounding, the treatment that leaves you believing that you really are a worthless piece of sh*t who deserves it. At least when you're hit, there's a mark, a scar, a cut -- something to point to and understand why you are hurting. With verbal or emotional abuse, though, you are always questioning why you feel so badly and wondering whether you were really treated as badly as you feel, and of course you start to blame yourself. And you can start to feel crazy and question your own perceptions and reality.