You will see differing opinions on this.
Did he know what he was doing? Yes and no. If he was dangerous and abusive, this, IMO, may have resulted from some kind of personality issue involving impaired conscience and empathy (among other things). So the abuse emerges from that: poor empathy, poor conscience, distorted view of the self relative to others,sense of entitlement, abnormal need for control, etc. You're not talking about a healthy person who just decides to be awful.
On the other hand there's a strong calculated element. They abuse some people and not others. They soon learn which tactics are most effective at achieving particular things.
Is he treating the new partner in the same way? If you are talking about two normal people, both with fully functioning empathy and conscience, a new partnership is a whole new deal.
But if you're talking about abuse: then if you argue that abuse emerges from deep within the personality, he will not have another nice personality up his sleeve for someone else. The honeymoon period is full of idealisation, idolising, adoring,perfection, etc,but when that's over....the new partner turns out to be a real human being with ideas of her own, even (shock) imperfections. And the old him starts to creep back.
However, you will also see differing opinions on this.