If you divorced during his employment you would be entitled to benefits under the 401(k) plan only if any of the following apply:
1. You were awarded an interest under the plan in connection with your separation or divorce as part of the divorce proceeding. Other conditions also apply under this item, including submitting a domestic relations order to the plan that is determined by the plan to be a qualified domestic relations order (QDRO).
2. Your ex did not remarry, left you as a designated beneficiary after the divorce, and the plan does not have terms that automatically designate someone other than you (former spouse) as a consequence of the divorce.
3. Your ex designated you as a beneficiary after the divorce and either did not remarry or complied with spouse consent rules of the plan if he did remarry.
My guess is if you did not get formally awarded an interest in the plan as part of the divorce proceeding (#1), you have no right to anything under the plan. It may be possible to get a court to award you an interest now, but that is unlikely under the law in most states. I know nothing about the domestic relations law of the F state. If awarding you an interest under the plan was not contemplated in the divorce proceeding and you were represented in the divorce proceeding by a lawyer, you might have a claim against the lawyer for malpractice. That would also be a matter governed by state law.