regret alot of things, feel like failed my son

[LucyWhite2014]

My DS is 27 and still a home. he doesn't and wont work, he couldn't even hold a job down. When he was younger he was SA by my ex h, who is in prison. DS 27 has been violent in past to brothers, and me. We have argued over cleaning and helping around house, he shouts he wishes I would die. so I do it all myself. One of these violent situations he punched his brother and ran out the house saying he would kill himself. I called the police and he was arrested. around a year after that he got a girlfriend, who was really supportive of him and his turbulent past. they were together on and off for 3/4 years, he was quite controlling I can admit. they eventualy ended for good in 2016, she was away with family and he was threatening her on the phone that he would kill himself. she was younger but very mature, when she came back from holiday she calmly said that she didn't want to be in a relationship unless he changed, but she cared and would still be a friend and there for him-as they had a lot of mutual friends. fast forward to present day.. said girl has since got married and my DS is still obsessed. He hasn't dated, seen any other girls since they split and says hes not over her. he keeps pictures of her on his phone and admitted to her he looks at them and does 'that' over them. even had a police visit she went to police due to harassment from him, messaging her constantly. Please help im at a loss with DS

It does sound like he is living with the legacy of what happened to him, it must be hard for you both in different ways.
Is he resistent to getting professional help for this? Does he recognise he is suffering from emotional damage and able to imagine things could change if he was able to heal in any way?
So sorry to hear about this it is awful what people inflict on others.

Has he had any counselling or therapy relating to the assaults by your ex husband, or any other mental health input? It sounds like he is really struggling to manage his negative emotions, and that's manifesting as violence, and controlling behaviour.

he recognises it and wants to change, he has a great counsellor and he does open up to her. he's a great lad at times I think we are both quite similar and just clash at times! thank you both

If he is spoiling his adult relationships by his behaviour it could result in more unhappiness in an ongoing way which in sure you'd both want to avoid. Can you task to him about the importance of positive change to enable a life with healthy relationships. He's still young but in ten years he doesn't want a trail of broken relationships behind him as his problems are only likely to be more entrenched with further rejection.
All you can do is support, guide and encourage him to try for positive change. It's the old adage of we all have a devil on one shoulder and an angel on the other, which one is stronger? The one you feed the most.
The more he fails to respect this nice girl who has been very understanding the more he becomes that person, someone who most people would avoid. He needs to try to envisage a better man of himself and actively work towards it.
Easier said than done though isn't it, but it's the direction hope lies if he can, with support, see it and try.