He beat her when he was drunk, because he couldn't handle his liquor.
He beat her when he was sober, because he hated the reality of his life.
He beat her when he thought she was ignoring his friends.
He beat her when he felt she was paying too much attention to his friends.

He beat her when he thought the house wasn't clean enough,
When the kids weren't quiet enough, or 
When dinner wasn't ready soon enough.

He beat her because she got blood on his shirt, when he was beating her.
He beat her because she "made" him beat her.
He beat her even though he "didn't mean to hurt" her. 

He beat her on the days he told her he loved her.
He beat her even though, he said it would never happen again.
He beat her the days she decided to leave him the 1st, 2nd and 4th time.
He beat her the week after, she came back the 3rd, 4th and 5th time.
He beat her the day he killed Her.