Is a divorce considered to have occurred, and is expiation required, for one who said to his wife: "By Allah, you will not lay a hand on it while you are still married to me," and then gave her what he swore about, knowing that he forgot his intention at the time of the oath, and three years have passed since then?

The statement "By Allah, you will not lay a hand on her while you are married to me" contains two matters: First: A conditional divorce by way of allusion. If the husband intended divorce, it occurs, according to the majority of scholars, upon the mere fulfillment of the condition it was contingent upon. Otherwise, it has no effect. Second: The affirmation of the conditional divorce with an oath. If the condition is fulfilled, an expiation for breaking an oath (kaffarat yamin) is due, whether the divorce occurs or not. If the condition is not fulfilled, no expiation is due.