To ensure a fair division of assets when divorcing someone you haven't seen in years, you may need to gather evidence of your financial situation and assets. You may need to disclose your assets and liabilities and negotiate with your spouse or their attorney. If your spouse is missing, the court may appoint a guardian ad litem or an attorney to represent them. The court may also consider other factors such as the length of the marriage and the contributions of each spouse to the marriage. Consult with a family law attorney for specific guidance on your case.