Prenuptial agreements mostly deal with what happens in the event of death or divorce.  But they can also be used to set up how a couple will handle their finances during the marriage.

It is also possible to put non-financial provisions, so called lifestyle clauses, in a prenuptial agreement.  So a couple can agree on who does which household chores, or how much television watching is permitted or even how may times a week you will have sex.  You can set a weight limit.  You can agree to a penalty for cheating.

Some couples view these as valuable provisions, sort of like a mission statement for their marriage or an extension of their vows.  Others find them to be negative saying that a marriage with lifestyle clauses is doomed from the beginning.

How they would be enforced is another question.  Will the court order an overweight spouse to lose 10 pounds?