If there are children from a prior relationship, they may not inherit when their parent dies without a premarital agreement. The laws of inheritance give preference to a surviving spouse. Even if a will exists, the law still gives preference to a spouse. The best way to make sure that children can inherit is to write a prenuptial agreement. When one spouse owns a business or a portion of the business in which they receive significant income, it may be desirable to make certain that the new spouse can't receive a portion of the business in a divorce. It can be devastating to the business to have a person own a business when they are not qualified to run the business. It can also be very difficult for one spouse to suddenly work for an ex-spouse.
Premarital agreements can successfully protect against these problems and others.