A prenuptial agreement is not set in stone. The court could throw it out, especially if you do something that invalidates it under the law.
Texas Family Code explains the court accepts prenuptial agreements after checking the validity and fairness of the arrangement.
One of the most important aspects of a prenuptial agreement is fairness. If the arrangement is terribly lopsided or obviously favors one spouse over the other without any explanation, the judge will probably throw it out.
You want to be sure that you are dividing assets and leaving each person in a good position with the agreement. While you certainly can look out for yourself and you can protect your separate property, you still need to be sure to provide for the other spouse. That could be through property division or a fair spousal support arrangement.
You also need to make sure you do not cover things the law does not allow in prenuptial agreements. You can cover property and spousal support, but you cannot use this agreement to dictate child support.
The judge will look over the agreement to determine if it is fair and if there are any items that would invalidate it. If the judge determines it is legally solid, then he or she will approve it. Once that happens, the agreement is in place should you later get a divorce. If the judge has an issue, you will have to make changes and resubmit for approval.
Remember that a prenuptial agreement is just a way to protect yourself in the event your marriage ends. It is not planning for a divorce or otherwise a bad thing. Everyone should benefit from the agreement as it should offer protection for both of you for the judge to approve it.