Someone give me advice

My fiancé left, packed a duffle bag and left. It started with him going out with 4 of his female coworkers and one of whom I’ve had problems with over her flirting with him in the past. He had drinks with them and I asked him out of respect for how much it matters to me not to. He said he won’t live his life like this and packed his things in front of my 5 year old and is gone. I tried calling him and he said I need to apologize and kept hanging up on me. Now he won’t answer me and apparently he had called his mom, who has gone through 4 marriages, and this was HER idea. She told him to leave me. I’m so broken right now, someone tell me I’m wrong and I need to call him and tell him I’m sorry. I don’t believe I’m wrong, but someone knock sense into me so I can get him back. I don’t know what to do..