What a Prenup Can't Do (and What to Do Instead)
/A prenup can do a lot more than most people realize but there are a few things it cannot do.
Knowing the limits up front saves time, money, and a lot of frustration. Here are the things a California prenup can’t do, and what you can do instead.
1. It can’t decide child support or custody
This is the one that surprises people most. A prenup cannot limit, waive, or set child support, and it cannot decide custody or a parenting schedule. Child support belongs to the child, not the parents, so the parents can’t bargain it away. And custody is always decided based on what is best for the children at the time, which no one can know years in advance.
What you can do instead: Talk about your values around parenting, education, and religion before you marry. If it helps, you can even write those conversations down outside the prenup. They won’t be binding, but couples tell me the conversation itself is worth having.
2. It can’t waive your spouse’s rights at death to most employer retirement plans by itself
Many employer retirement plans, including most 401(k)s and pensions, are governed by federal law. That law automatically gives a surviving spouse rights to the benefits. The catch is that only a spouse can waive those rights, and when you sign a prenup, you aren’t married yet. So even if your prenup says your 401(k) is your separate property and goes to your kids, the plan may still pay your spouse if you die.
What you can do instead: Include a promise in the prenup that your spouse will sign the plan’s waiver forms after the wedding. Then actually sign them, ideally within the first few weeks of marriage. This is one of the most common loose ends I see, and it’s easy to fix while everyone is still on the same page.
3. It can’t guarantee a spousal support waiver will hold
California does allow you to waive or limit spousal support in a prenup, but with two big conditions. First, the person giving up support has to have had their own attorney when they signed. Second, a court can still refuse to enforce the waiver if enforcing it would be unconscionable, meaning so unfair it shocks the conscience. And the court looks at fairness at the time of the divorce, not when you signed. A waiver that seemed perfectly reasonable when you were both 30 and working can look very different twenty years and two kids later.
What you can do instead: Instead of a full waiver, consider a limit that holds up better over time, such as a cap on how long support is paid, or a schedule that grows with the length of the marriage. Agreements that build in fairness for the future are much harder to set aside.
4. It can’t punish bad behavior
Infidelity clauses get a lot of attention online, but California is a no-fault divorce state. Courts here have refused to enforce prenup provisions that penalize a spouse for cheating, drug use, or other conduct during the marriage. The same goes for lifestyle rules like weight limits or how often you visit the in-laws. A court won’t referee those, and it won’t move money around because someone broke one.
What you can do instead: If something really matters to you, talk about it directly before you marry, and consider couples counseling to work through it. A prenup can still include statements about your shared intentions, as long as you understand they are expressions of values and not enforceable penalties.
5. It can’t fix a rushed or one-sided process
A well-written prenup can still be thrown out if the way it was signed wasn’t fair. In California, each person must have the final agreement for at least seven days before signing. Both of you need to fully disclose your finances. And the agreement has to be signed voluntarily, which courts take seriously when one person had a lawyer and the other didn’t. A prenup handed over the week of the wedding is exactly the kind courts look at closely.
What you can do instead: Start early. I recommend beginning the process at least three to four months before the wedding. That leaves time for disclosure, negotiation, and review without anyone feeling pressured.
6. It can’t protect what you don’t keep track of
A prenup sets the rules, but you still have to live by them. If your agreement says your premarital savings stay separate and you then mix them into a joint account and spend from it for years, proving what’s still yours gets very hard. The same goes for adding your spouse to the title on a house during a refinance, which can turn your separate property into shared property, prenup or not.
What you can do instead: Set up your accounts the way your agreement assumes, keep good records, and check with your attorney before making big moves like retitling property. A short review every few years, or after a major life change, helps keep the agreement and your real life in sync.
The bottom line
A prenup is a powerful tool for deciding how your finances will work, but it isn’t a contract for everything in your marriage. The best agreements are the ones written with their limits in mind: they focus on what the law will actually enforce, and they leave room for the parts of life no document can predict.
If you’re thinking about a prenup and want to understand what’s possible for your situation, schedule a free consultation. We can talk through what you want your agreement to do, and what it can’t.