Sometimes I think "these guys" have poor impulse control. I think, if DP killed Stacy, that it wasn't planned. I think her leaving that morning to go paint was what he thought to be an excuse to meet a man for an affair and he went off in a jealous rage.
Now, he misses her. He gets sad. Such is the "stuff" of Greek drama. Not to mention, the bible. Men who killed their wives, or had them killed in the heat of the "moment" and then later regretted it.
I think players can never "relax", it's been my experience that they expect every woman to do to them, what they have done to women. IMHO