Is lying the same as cheating?

My husband lied to me about a long time female friend. After 9 years of marriage, I found out his "platonic" best friend and he had a ual relationship before we met. Even though it was before we met I feel I deserved to know the truth BEFORE. He has since ended his friendship after knowing how badly I feel. I feel even though this was only a lie, I actually feel cheated on. Is lying the same as cheating?