The general rule with an inheritance is that it is not marital property, but separate property. Say your parents leave you $100,000 when they pass away. Later that year, your spouse files for divorce. Most of the time, the court looks at that $100,000 as separate property that belongs only to you, so you do not have to split it with your spouse.
However, there is one main issue that may turn your inheritance into marital property, and that is sharing it with your spouse. Often, this means commingling it with other funds by putting it into the same bank account or buying assets with your spouse.
For example, maybe you and your spouse decided to buy a new car. You put the money into your joint checking account, and then you took out the money for the loan down payment from that account. You got the loan together. Going forward, you used the balance of that account, which you and your spouse both had access to and used for your paychecks from work, to make the monthly loan payments.
But doing all of that, you showed that your spouse also had a right to the inheritance during the marriage. That makes it a marital asset. You likely cannot claim that you still get $100,000 out of that account or that the car is now yours alone, rather than a jointly owned asset.
If you have any questions about how asset division works, it is important to address them quickly as the process plays out. You need to know all of your rights and obligations.