Spousal Support and Alimony: Does Cohabitation End Spousal Support

My question involves marriage law for the State of: Va.

I was told if my ex cohabitation with another after divorce for a year. She would no longer be initiated to my spousal support or my retirement in which she is getting both.

if this is true and how do I document this? Does she need to remarry or just live with some one ?

Spousal Support and Alimony: Does Cohabitation End Spousal Support