Musannaf Ibn Abi Shaybah 19028 — A man who has two wives and forbids

Ibrahim (may Allah have mercy on him) said: If a man has two wives and forbids one of them from going out, but the other wife, whom he had not forbidden, goes out; he thinks it is the one he forbade, so he says, "So-and-so, you went out? You are divorced" — in this case both are divorced: the one he named because of his naming her, and the other because of his saying to her, "You are divorced."