Confused

I found out my husband like someone else. He told the I girl I like you but we can't have these relationship because I have a wife and kids. Then the girl keep inviting my husband to meet @ fast food with her kids and our kids to cover them up. The girl husband fool around with their co-worker. All of them work together. We've been marriage for 11 years. I asked my husband not to meet the girl and he said okay. But when he left @ home he called @ his work that his coming late to work. When we fought he always defending the girl that she is good woman. You called that good woman that you keep inviting the man to meet you. They keep texting each other even midnight until early morning. My husband came back to me but it doesn't mean he still love me. he came back because we have 3 kids and I just gave birth 2 1/2 months ago. I'm so confused now, still in my mind to get divorce but my kids will be affected. It's hard to live that the man you love, like someone else. Please give me some advice what to do.