You should have a QDRO (Qualified Domestic Relations Order) regarding IRA / Retirement Accounts. The QDRO will address the taxation of the portion of the plan that is distributed to you. Typically, this money has not been previously taxed and any distributions you take will be taxed at ordinary income rates. If you are not yet 59 1/2 there will also be a 10 percent penalty.
Any individual seeking legal advice for their own situation should retain their own legal counsel as this response provides information that is general in nature and not specific to any person's unique situation. Circular 230 Disclaimer - Advice given in this response cannot be used to eliminate penalties with the IRS or any other governmental agency.