No, there is no legal requirement that a lawyer review your Separation Agreement. If it is a “plain Jane” agreement where you are using formulas for everything and not deviating from any of the statutes, it is likely unnecessary that an attorney need review the agreement.
In this example, I conduct an agreement review session with you, before you sign the Separation Agreement, so that there are no misunderstandings and everyone is clear about the terms.
If there are businesses involved and/or complicated assets, then I would urge a couple to consult with accountants, and get the businesses valued by a business valuation expert. I can provide you a list of accountants and business valuation experts that I trust.