In Florida, couples do not need a reason for divorce other than their marriage is over. In fact, Florida is a no-fault divorce state which means that even if the actions of one party led to the end of the marriage (an affair), that action is not considered in determining separating assets, debts or determining alimony (spousal support).
In a Florida divorce, the object is to separate marital assets and debts and put the parties in a position that is as fair as possible. Equitable distribution is the term used to divide the marital properties and works to do just that, equally divide the property (assets and debts) between the parties.
However, if one party uses marital money to benefit an affair, then the other spouse is entitled to half of the money used for said affair. For instance, if a wife uses $10,000 to travel with her boyfriend, then the husband is entitled to $5,000 of that money. In a divorce, if there is not $5,000 in cash available, then assets may be divided differently than 50/50 to make-up for the lost money. For example, if the assets total $20,000 then instead of $10,000 to each party, they may be divided so that a greater portion is awarded to the husband to compensate for the $5,000.
The idea is to place the non-offending party in the same position as s/he would have been without the existence of the affair. It is not designed to punish or award either party.
If you are filing for a divorce and are seeking this type of compensation, it is important that it be asked for in the beginning. When you file for divorce you actually file a petition with the court, which should outline what your interests are in the outcome. Typically, the court will default to equitable distribution unless a party requests a greater than 50/50 division. It is a good idea to speak with an experienced lawyer to help you understand your rights and options before filing.