It doesn't seem to me like there's much of a "right" answer to this one. If you wait for the child to be gone, it's WAY too late for your family and if you eat with the dc child, where is your family time gone?
I think the problem is your hours. Is it a long contract? I think you need to have definite hours that work for your family and they are non-negociable.
That's my 2 cents, anyways....