Relationship Confusion. Need advice 😞

How do you know when's the right time to end a relationship after a series of verbal abuse and series of reconciliation?

The guy acts all nice one moment and the next he's a whole new creature.

We communicate perfectly in bed ans after that we're like 2 strangers trying to understand ourselves.

Everything was real smooth in the first 2 years of the relationship. Then he started communicating with the ex again. We split and eventually started afresh . But since then, i feel he's taken/seen me as 'cheap' or crap....i really don't know. He just changed. We'll be 4yrs by November. He told me this in the face: "You think you'll be with anyone better if you leave me?"

He's raised his voice at me and rained insult on me, many times than i can count but i still remain with him, with the hope he'll change to the person i first knew.

And At times i get scared of leaving him😞.

I don't know what to do.