OP here. Not the same. In the situation I am describing, old wife cinitues to live in the family home with the kids. Man lives in new woman's place, and every 15 days he comes back to old wife's house and spends the weekend there, in a separate room. Old wife sticks around. New woman never sets foot in that home -- and never sees the kids.
In the meantime, during 12 out of 14 days, old wife is basically a single mother, and man is completely absent.
In the situation I am describing, man thought it was toooo compkicated to be taking care of the kids without the old wife (and without the new woman's participation) because he works long hours.