A Pre Nuptual Agreement will protect you before you get into the marriage and after. It all depends on how your attorney words the agreement just like a real estate contract. Not all agreements are the same.
See one thing that I have learned in life, you cant give your spouse (man or woman) all of your power. Yes, you are head over heals in love right now, but what about later. One thing that is true about humans, we are unstable as heck. At least some of us are. Why give away all of your hard earned blood sweat and tears to someone that wants to burn you? But i guess it just takes experience to see.
Another thing, make sure all of your assets and businesses are in trust. Make sure all your trust are in the name of a trustee that your spouse cant track. Make sure you trust your trustee.
If your spouse knows about all of your business ventures then that is so your fault. There is no reason for you to go reporting all of your business ventures to your spouse unless he or she is part of these business ventures. In most cases they are not, but like to see the money coming in. Not saying that you should be dishonest in the relationship, but dang bro, if she is not a business oriented person....She is planning the come up. She will always know that if she wants to leave tomorrow, your hard work will be hers, even if she did not help you out one bit with these ventures.
I would also look into Swiss accounts and over seas investments. Also, buy some gold bars and take them to Germany and keep them locked away.
p.s. Nothing against woman in this post. I have seen the same thing happen to women in this business taken advantage of from men looking for a come up.