Equitable distribution of retirement accounts in Florida, including 401(k) accounts, is governed by Florida Statutes 61.075.
To first determine if in fact a particular retirement account is a marital asset, you first have to understand the definition of a marital asset. A marital asset is defined as any asset acquired during the marriage, either individually or in joint names. Although there are other aspects to this definition, this is the primary definition.
Marital assets also include all vested and non vested benefits, rights, and funds accrued during the marriage in retirement, pension, profit-sharing, annuity, deferred compensation and insurance plans and programs.
We can see that retirement accounts, including a 401(k) account, even if it is in the name of one party, it will be considered as a marital asset if all of it or a portion of it was acquired during the marriage.
Giving up any portion of a retirement account that was accumulated during the course of a marriage can be a "difficult pill to swallow." The usual reaction by an individual is that "I worked hard my whole life for that money", and "I'm not going to give up one penny of of it."
You may not necessarily have to give up a portion of the asset, but you most certainly will have to give up 50% of the value, and offset it against other assets.
Psychologically, I know it is difficult to surrender an asset many consider to be very personal. A recent article from a Jamaican Newspaper demonstrates the global aspects of an individual's view of his or her retirement accounts. They will fight to the end to protect what they perceive as their own individual assets.