Hello,
Thanks for your query.

I appreciate your efforts for medical consultation in so much distress.

First as your boyfriend was in prison and in more than 70% of person with imprisonment history have inbuilt aggressive personality irrespective of cause of imprisonment. Most commonly we see dissocial personality in such persons or some of the qualities of dissocial persons.

Behavior pattern in Dissocial personality persons:
(1) Callous unconcern for the feelings of others.
(2) Gross and persistent attitude of irresponsibility and disregard for social norms, rules, and obligations.
(3) Incapacity to maintain enduring relationships, though having no difficulty to establish them.
(4) Very low tolerance to frustration and a low threshold for discharge of aggression, including violence.
(5) Incapacity to experience guilt, or to profit from adverse experience, particularly punishment.
(6) Marked proneness to blame others, or to offer plausible rationalizations for the behaviour bringing the subject into conflict with society.

Your boyfriend may have some of above or related features. With time and social learning some of the features subside with age but, as he was imprisoned due to that he was surrounded many persons having some of the above behavior pattern. Due to that inherent body tendency of maladaptive behavior become apparent and person also learn some of new behavior to adjust in this environment.

Medicines also help in several cases. But you may have limitation as your BF may deny for visiting psychiatrist or taking medicines. Although it is difficult to change behavior with such limitations but you may give your efforts in form of behavior therapy. But it will take months to some change in behavior, so you need to remain motivated during the process.

For any behavior modification program behavior analysis is first step. It is better done in person visit with psychologist trained in behavior therapy. The first step is doing ABC Charting of maladaptive behavior. ABC chart for behavior problems can be get on net after google search (Search words: ABC chart for behavior pdf). It is very effective for children and adults.

The Antecedent Behavior Consequence (ABC) Chart offers opportunities to note the setting, time and frequency behaviors occur, what happened just before the behavior, a description of the behavior itself, and the consequence of the behavior. By noting behaviors in this ABC Chart, you may be able to more accurately focus on the origin of undesirable behaviors.

After charting of maladaptive behavior behavior modification technique like positive reinforcement, punishment (by avoiding conversation or other means) and modelling can be use. It is complicated task and planning may vary case to case. It is better to discuss about specific maladaptive behavior with therapist. If you have some specific maladaptive behavior related query after behavior analysis, you can ask us too.

I hope this information has been both informative and helpful for you. In case of any doubt, I will be available for follow ups.

Wish you good health.
Regards,

---