Pos-nuptial agrément

I am Brazilian, I got married to an American in Santa Clara California on December 31, 2019. I already had properties in Brazil before. In 2022, I  sold one land property there in Brazil and bought another one to replace it. However, the money wasn't enough to pay the house in cash, because I used a big part of the money to organize the other properties' taxes, and documents, from my divorce with my first husband, and other debts. For the house I bought ( They are building it, should be ready in October 2024, I am paying the mortgage. I don't send any money from the US to invest there. But now I would like to guarantee that my current American husband will not fight for me to divide this property with him in a divorce case. He always leaves it clear to me that he will never buy a house for us because his ex-wife stole everything from him on their divorce and I won't take anything from him. He doesn't have anything. Adult children here. We are old and we don't have kids together. I have my adult children in Brazil and he has two We live like roommates, and he wants me to pay half of everything. I work as a home organizer, I don't make much money, he is a patent attorney but doesn't like to work hard. This offends me deeply. Because I don't want anything from him. When I mentioned that I wanted to make this post-nuptial agreement addressing that the properties we buy after the wedding, will be independent. Separated. He said he wanted to do it because he would add other clauses that in case of divorce I would not have the right to this or that. But But its been a year since he procrastinated to do it and hasn't done it.  I don't know anything about family laws here.