An Alford plea is equivalent to a guilty plea, but the defendant maintains innocence while admitting there is enough evidence to likely result in a guilty verdict.
Sandra McMillan is charged with murder and felony child abuse in the death of the couple's son Tyler. Prosecutors say the couple tied the boy to a tree to punish him and he died of sun exposure.
The wife's trial is set to start in July, and Brice McMillan will be sentenced afterward.
Sandra McMillan has been free on bond since March. A judge ordered her to live with her cousin in Cary and wear a monitoring device. Bruce McMillan has been in jail since his arrest in June 2008.