As a cautionary tale, something happened with ex before we got married.
He was being very jealous, aggressively so, to the point that I really lost it and was offended and slapped him (me, being half his volume). He just grabbed me by the neck and pushed me against the wall.
Nothing horrific, but it did leave some pressure marks.
At the time I had a long think and a big talk with him.
Essentially, he was told if anything like this was to happen again we would be finished.
We got married more than a year later, been married over 10 years and suddenly last year he attacked me again. :-(
I suppose some men may actually be able to change, but if the instinct is there, I don't think it will ever go away.
Like alcoholics, they will be for their lives.
The only reason I don't regret my initial decision is DS, who is the best boy ever.