No, but it is a good idea. Lawyers can help make sure that the agreement is drafted properly and that both parties are making informed decisions. The lawyer for the wealthier party usually prepares the initial draft of the agreement. The less-wealthy party should also have a lawyer to review the agreement, even if only on a minimal-cost consultation basis. Although you do not need to have a lawyer in order to have a valid agreement, the agreement is more likely to be enforceable if each person's interests are represented and significant back-and-forth negotiations have taken place. The agreement is more likely to be challenged if one of the parties does not have an independently chosen lawyer.