I don't agree with the whole "emotion driven to do things they wouldn't normally do" statement in this case, although in many others it most certainly does apply. There are a lot of very good, law-abiding people that often feel pushed to the point of desperate acts.... and then there are still others who regardless of how badly life fucks 'em, they take their lumps and try to move forward the best they can.
This guy had a proven pattern of escalating abuse and control, that's why she divorced him. He became beyond enraged when she began living her life again WITHOUT him....
Lotta women go through this bullshit and as in this case too (he murdered her instead of trying to fuck w/her by taking her kids as waaaaaaaaay too many men do when they chicken out of actually doing what they fantasize about on a regular basis) we see a TERRIBLE failure by the court system.
C'est la vie.