It's really hard and developmentally inappropriate for a could to know that their father (funday) didn't love them our care for their mother. If they get that thought into their subconscious as their primary relationship blueprint, that is the only thing they will attract and notice unless they do extensive work on themselves.

Children also can't see grey situations, so daddy either loves me unconditionally, and thinks about me all the time and he's always there, or he doesn't and isn't. If a parent implies something is wrong, then that means daddy or the relationship is wrong. It's sort of the same logic when you only want to show your children a unified front in major decisions, whereas disagreeing and coming to agreement is a not complete picture of the situation.