While some married couples in Panama City are happy to say "what's yours is mine and what's mine is yours," there are situations in which one spouse may wish to retain sole ownership over certain types of assets, such as an inheritance. In general, an inheritance is considered to be separate property, rather than marital. However, should commingling occur, this once-separate property could be considered marital for property division purposes in the event of a divorce.
Of course, the specific laws on commingling vary by state. However, in general if separate property -- including an inheritance -- is used by the person who owns the property in a manner that ultimately ends up benefiting marital property, commingling has occurred, and the separate property may now be treated as marital property.
For example, a person could put their inheritance in a joint bank account used by both spouses during the course of the marriage. If these funds are then used to pay for marital expenses, the inheritance will have said to have commingled. In addition, if a person receives an inheritance and uses it to fix up or renovate their marital home, this is another situation in which the inheritance will haves said to have commingled.
In the end, if someone has an inheritance or is expecting an inheritance, and wants to avoid commingling issues, then they may want to enter into a prenuptial agreement prior to getting married. A prenuptial agreement can specifically state that the inheritance is to remain separate property in the event of a divorce.
If a person does not have a prenup, is facing the issue of commingling in a divorce, but never meant to commingle assets, if the person can show that he or she never meant to commingle assets, then the assets may be considered separate property once more. However, this is a very, very high standard to meet, as it is presumed that funds in joint accounts were meant to be shared. In either case, seeking the advice of a family law attorney can be imperative to achieving a fair result in the divorce process.
Source: FindLaw, "Inheritance and Divorce," Accessed April 17, 2017