Men, Women, Murder and Punishment in the US?

Most murders by women, the victim is a close friend or family member. I think that fact makes the murder especially heinous. I don't know what percentage or the murderers were abused by their husbands but I don't see that as an excuse. For one, if it was self defense, etc, they would not have been convicted of 1st degree murder. It would be something lesser like manslaughter and two, I'm fairly certain a good percentage of the men were likely abused themselves at some point in their life. It seems childhood abuse almost always leads to screwed up adults.