These two things happened:
My marriage ended.
You get divorced after a dozen years of marriage, the adoption of one black feline, and the creation of two small humans. It is, as expected, horrible for all involved, but especially for the children who can no longer see you in the same room without their stomachs knotting.
You are opposing ends of a magnet. When one is present, the other must not be within shouting distance, not that there was ever much shouting. Still, it becomes a calendar of conflicting schedules, and payments due, and avoidance. It is the avoidance that is the most difficult, as you see the children adapt to a life of either/or.