Nothing like a good bedtime routine
Put my son to bed last night and told him sleep is just a trial for death. Wife shot me a look and told me to get out of the room. I said okay I'm leaving, don't want to be around for the existential crisis I just caused. He cried laughing though so I'm calling it a win. Parenting is weird man.
Dark dad humor is absolutely necessary for survival. Your wife will get over it. If you can't make existential jokes at bedtime then what's even the point of being a parent.