How can I protect my settlement money in the event of a divorce down the road?

Location: California

Not sure if I tagged the right type of law for this situation. I recently received some settlement money, but have not yet cashed the check. I am married, and while I don’t anticipate a divorce, I want to make sure I am protecting myself if it ever came to that in the future.

We have no prenuptial agreement. Before we got married, we both had some settlement money from before we met in separate investment accounts. After we got married, we created a joint checking account and a joint credit card, but agreed that our investment accounts would not be co-mingled. We ended up opening a joint investment account for our joint funds to invest with.

Before we got married, I only had the one investment account at the time so I funded that same account with savings. After we got married, I was told not to add to that account or it would automatically all become joint property (I’m not sure if that’s the correct verbiage or if that is true) so I haven’t added a penny to that account since before we got married.

Now, I have some new settlement money coming in from a horrible injury I sustained. The accident occurred prior to our marriage, but the settlement money only came after our marriage.

I want to know how I can best protect this money from becoming joint assets. Can I add it into my single name investment account? Do I need to make a new single name investment account? Do I need to create some sort of a trust or something? I would prefer to add it to my existing account, but don’t want to mess it all up if that is wrong.

Thank you for your help!