Ask the Expert: how to handle a divorce (Part 1)

My husband had slept with an old fling while I was pregnant with our second child and I was due to give birth the very next month. I was so upset because I was always pregnant and alone looking after our active toddler and he kept claiming to be working hard driving for Grab and falling asleep in the vehicle after. Lies. And I only found out about it exactly a year later when my son was almost 1. He also has a terrible temper. He is awfully abusive both verbally & physically. But he is seen as a very nice person to many because, well he’s very nice to friends and outsiders. I was his friend first so I can attest to that. I suspect he has a personality disorder. Is this marriage even worth saving?