If I had some bitcoins before I got married, and used bitcoins to buy houses, cars, etc.
When the price of Bitcoin went up, I sold Bitcoin. Is this my money my own? Or is it shared by husband and wife?
When I get divorced, do I split up my bitcoins?
Well, it always belongs to the conjugal properties which mean your partners can anytime claim what's you have.
As everyone has noted, --if you are residing in a place where the law permits interfering with cryptocurrency holdings, it will be surely legally split as husband and wife when you get a divorce. However, if you own bitcoin before you marry and haven't sold it or used it to pay for something during the marriage, I also believe it cannot be declared as common or it is still separate property.