Did divorce take place on any of the four occasions when the husband uttered the word of divorce: 18 years ago, 3 years ago, when the wife said, "If you leave, you are divorced by triple talaq," and two months ago?

An explicit divorce takes effect and does not require an intention. Therefore, the husband's saying "You are divorced" in the first and second instances is effective without any ambiguity.

As for the husband swearing by triple divorce intending to prevent his wife from leaving, not to effect a divorce, this is a matter of dispute: 1. The majority of scholars: Hold that divorce occurs upon breaking the oath, and that a divorce pronounced three times counts as three. 2. Ibn Taymiyyah: Is of the opinion that the ruling on swearing by divorce, when it is not intended to effect divorce but rather as a threat or emphasis, is the same as swearing by Allah. In this case, expiation for breaking an oath becomes obligatory upon breaking it, and no divorce occurs. If divorce is intended, he holds that a divorce pronounced three times counts as one.

As for the third instance where the wife is unsure if the husband uttered the divorce and he denies it, the husband's statement is fundamentally accepted. However, if the wife is certain that he pronounced an explicit divorce, then three divorces have been completed, and it is not permissible for her to remain with him. She must redeem herself through khul'.

It is advisable to present the matter to a Sharia (definition) court or trusted scholars.