Hmmm. Seems the man did a terrible thing to the woman’s life here. But if you insist on blaming the victim, go right ahead, I’m sure you have your reasons.
I have no idea what set him off. I had a friend and former classmate do exactly the same thing as Belcher. He pulled out a gun at a party while his very young children were sleeping in their bedroom. Shot his wife dead in front of witnesses and just as the police arrived, went outside and ate the gun. In his case, he was high on drugs.