Congrats on the degree! You really have moved on! Have you sorted through this with a therapist? I'm going through stuff I never sorted, and it's been 7 years since the incident happened. I also (along with all my childhood abuse) had an abusive relationship 20 years ago and wondered if his new wife was ok. I never focus on him anymore but for awhile I did. I moved across the country to be safe and even after that the police called me because he was being vetted for a position in government.
I personally don't think abusive people change unless they go through therapy and want to change, or have a life altering experience. Even then it's easy for them to fall back on bad behaviors to cope. I'm glad you're doing well and have a good relationship.