Is my ex still the beneficiary on my 401(k)?
Unless you filed a new designation, your ex is very likely still named, and that designation controls. A beneficiary form beats your will. If you die with your ex named on a 401(k), the account goes to your ex no matter what your will says and no matter that you are divorced.
This is the item on the post-divorce list with the worst consequences and the smallest effort required, and it is the one most often left undone.
Why "the divorce handles it" is usually wrong
Nearly every state automatically revokes what a will leaves to a former spouse. But for beneficiary designations on life insurance and retirement-type accounts, only about half the states have an automatic-revocation law. Those laws are real, and people quite reasonably hear about them and stop worrying.
The complication is that they do not reach every account, and the ones they miss are usually the largest.
Employer-sponsored retirement plans, and many employer-provided life insurance policies, are governed by a federal law commonly called ERISA. Federal law generally takes precedence where it conflicts with state law, and for plans ERISA covers, the administrator is required to pay according to the plan's own documents and the designation on file with them. Courts have consistently held that a state's automatic-revocation statute cannot override that requirement.
So the same question has different answers depending on where the money actually sits:
A 401(k), a private-employer pension, and employer group life insurance are usually ERISA plans. The form on file governs, and your state's automatic rule probably does nothing.
But ERISA does not cover government or church plans. A 403(b) at a public school, a state or municipal pension, and a church-sponsored plan sit outside it, and there your state's automatic rule may actually reach the designation. This is a large exception and it catches teachers, nurses, and public employees in particular. Ask the plan administrator in writing whether the plan is governed by ERISA, because the answer decides which body of law applies to you.
IRAs are usually not ERISA plans, so state law may apply. But the custodian still follows its own documents and the designation it holds, so this is not something to rely on either.
A life insurance policy you bought yourself is usually a matter of state law.
Federal employee and military coverage runs on its own federal rules, which override conflicting state law. A state law that automatically strips an ex from a designation does not reach federal group life insurance, so the form itself has to change. There is one route worth knowing about for federal employees: a divorce decree or a court-approved settlement can control who gets FEGLI, but only if it says so expressly and only if the employing agency, or the retirement office once someone has left service, actually receives it before the insured dies. Filing it with the divorce court is not enough. If that matters in your case, name it in the decree and then confirm the agency has a copy.
There is a second wrinkle worth knowing even where a state law does work as advertised. Revoking a designation removes a name; it does not choose a replacement. That can leave the account with no valid beneficiary, which sends it to the plan's default order of payment or into your estate, and neither is necessarily where you would have sent it.
The practical translation is the same in every one of these cases: do not rely on any automatic rule, in either direction. Name the person you want, in writing, with the institution that holds the account.
What to check, and where
Employer retirement plans, meaning a 401(k), 403(b), or pension. Through your employer's benefits portal or plan administrator.
IRAs, with the institution holding the account, separately from anything at work.
Life insurance, both through your employer and any private policy.
Health savings accounts, which have beneficiaries and are widely forgotten.
Payable-on-death designations on bank and brokerage accounts.
Then the documents that are not beneficiary forms but do the same job: your will, your power of attorney, and your healthcare proxy. Divorce does not automatically remove an ex from these everywhere, and the healthcare proxy is worth pausing on, because it decides who speaks for you if you cannot. Whatever your relationship is now, that is a decision to make deliberately.
Two things to check before you change anything
Your decree may require you to keep someone named. This is common where life insurance secures a support obligation: you may be ordered to maintain a policy naming your ex or your children while support runs. Changing it in that situation violates the decree. Read what yours says.
Some accounts cannot be changed while the divorce is pending. Some states impose automatic restraints on exactly this once a case begins, binding whoever filed straight away and the other spouse once they are served. Your will is generally outside those restraints, so that piece you can usually see to right away. So the sequence is: check what you are permitted to do, then do it the moment you are allowed.
If you have remarried
Federal rules generally give a current spouse rights in workplace retirement plans, and naming someone else often requires that spouse's written, notarized consent. Assuming your new marriage automatically redirected the account is another version of the same mistake.
Do it now, and confirm it
Five minutes per account, and the confirmation matters as much as the change. Get written verification that the new designation was received and recorded, and keep it. Plans lose forms, and the person who would find out is not you.
The rest of the after-the-decree list covers what else belongs in that same stack, including the retirement division itself, which needs a separate court order that is frequently never filed. If that order divides your ex's plan, make sure it says expressly that you keep the survivor benefit. Being an ex-spouse does not carry the survivor protection a current spouse has, so without those words your payments stop when your ex dies and the survivor benefit goes to whoever they married later. Nothing gets rejected, nothing looks wrong, and nobody finds out until it is far too late to fix.
Which plans fall under federal rules, whether your state has an automatic revocation statute, and what your decree requires you to maintain all interact in ways worth confirming. If significant sums are involved, this is a good use of an hour with an attorney or a financial professional.