Remember the premise, cheating is lying about the situation, and acting on those needs without consent.

There is no world where that is healthier than whatever mutual agreement the couple could end up in, after honestly sharing their situation.

If the care for the needs of the child is real and actually shared between the parents, anything ranging from a sexually open marriage, to a divorce with uninterrupted coparenting, is leagues better than pretending you want to be there while actually both having a bad time around your child’s other parent, and constantly lying.