Texas law provides that all provisions in a will in favor of a former spouse “must be read as if the former spouse failed to survive the testator” and are null and void. Therefore, if you get divorced and don't change your will, you ex-wife will not inherit under your will even if you want her to inherit from you. You would have to make a new will after the divorce in order for her to inherit from you under your will. Of course, if you don't want her to inherit under the will, the law voids all provisions for her. To be safe, you need to change your will if there is a divorce. A recent case decided by the Texas Supreme Court, In re Estate of Nash, shows how expensive litigation can result if you don't change your will.
Nash's Will left everything to his wife, or if she predeceased him then to his stepdaughter. Nash and his wife later divorced, but he never changed his Will. Nash died and both his ex-wife and her daughter, Nash's step-daughter, survived him. A relative filed for probate seeking all of Nash's property for Nash's other heirs at law saying that the provisions in the will giving everything to his ex-wife and his ex-step-daughter were no longer valid. Since the will made no other provisions for the property, the relatives said that the property went to Nash's heirs at law (nieces and nephews, etc.). In contesting the probate, the ex-stepdaughter said that the property belonged to her arguing that Texas law treats the divorced wife as having predeceased Nash therefore the provision that if his wife predeceased him everything would go to the step-daughter came into effect.
The Court ruled against the ex-step-daughter and in favor of the relative, holding that since the ex-step-daughter only took under the contingency that her mother predeceased Nash, the ex-step-daughter did not inherit because her mother was still alive. This is true even though the Texas statute treats the mother as having predeceased Nash!
Nash may have had a good relationship with his ex-wife and/or with his ex-step-daughter (the Court doesn't say) but even if he didn't change his will because he thought it would all go to them, he was mistaken. And what would have happened if he didn't want his his ex-stepdaughter to get anything and his ex-wife would have died before him? Would his ex-stepdaughter inherit then because she survived the ex-wife? That question wasn't answered since the ex-wife was still alive. The moral of this case is that you need to redo your will after a divorce or the courts may decide who gets your property.
Section 123.001 Of the Texas Estates Code, formerly Section 69 of the Texas Probate Code provides that after divorce the wife and all her relatives who are not relatives of the testator will be treated as if they failed to survive the testator. This makes it even more important to make sure your will is up to date in the event that you get divorced.
There are situations where a divorced spouse may be entitled to something that most people would think comes from their former spouse even after a divorce. The Texas Supreme Court says that a divorced spouse will receive payments based on their former deceased spouse's retirement from a state retirement fund when: the former spouse was part of the Teacher Retirement System; who took reduced retirement payments so that their spouse would receive a reduced portion of their benefits after they die; who then get divorced; and, who do change their beneficiary under the plan. The Court said that once the divorce is final, the spouse who wants to deny benefits to his or her former spouse is required to follow the procedure set by the Texas Retirement System and use TRS's forms. If they don't follow the procedure or use the proper form, the divorced spouse will receive the retirement benefits after the death of the worker. In this case, the husband had waived his right to the wife's TRS benefits in the divorce decree. The court said that it doesn't make any difference what the divorce decree says if the procedure is not followed and the proper forms are not used. 221 S.W.3d 622.
In a prior case, the Supreme Court had held that a spouse could waive the beneficiary designation in a divorce decree of retirement funds under ERISA. In explaining the difference between the ERISA retirement funds and the TRS retirement funds, the Court said "...but the benefits at issue in (the ERISA case) were payments under simple annuities purchased by the employee (and could be waived) and were not at all like the carefully regulated optional annuity provided by TRS involved in this case (which could only be changed by following TRS's procedure and using their forms)." 121 S.W.3d 721.
UPDATE: A Missouri appeals court decided that a contractual will did not survive a divorce. Missouri, like Texas, has a statute that nullifies all provisions in a will in favor of a spouse if the spouses divorce. In the Missouri case, the husband and wife had a contractual will. They divorced. The husband did not change his will. He died. The ex-wife filed the contractual will for probate saying that the contract between the deceased husband and her survived the divorce. The appeals court said it did not. Even though the parties contracted to make mutual wills, the wife would be treated as if she had predeceased the husband under the statute that nullifies provisions in favor of an ex-spouse.