How do I know whether he is good for me or not?

My husband and I have been married for almost three years. When we were dating I felt I had met the love of my life - not because of grand gestures, but because I felt genuinely comfortable with him.

Before we got married he cheated on me. We broke up, he was devastated, and I eventually forgave him. We got married and it was genuinely good. He would bring food to my office, take me for ice cream at midnight, plan a beautiful full-day birthday for me, make handmade cards. When I was clumsy and broke things he would calmly clean up and comfort me. There was so much warmth.

But over time the fights got uglier. He would threaten divorce, send me 'settlement money,' withhold the car, go completely silent for weeks. My anxiety would peak and I'd beg just to go back to normal - apology or not. That cycle repeated every few months and then to every few weeks.

There was a holiday where he left me at a train station. There were times he told me things I remembered clearly were 'all in my head.' During long distance he blocked me because I asked him to call.

Then he actually filed for divorce. An official application arrived in my email. I left the house for five days. He didn't tell anyone where I was or check if I was safe. A week later he was crying and begging me to come back.

I've been holding my ground. My therapist says he has narcissistic abusive traits and that separation is the right step. He says he's changed, he's started therapy, he's identified childhood trauma. He's had a few sessions.

But I've been here before. I know he'll eventually say 'separation is done, I've changed, come back.' And I don't know how to judge real change from the trap. How do I know the difference?