TW: Domestic Violence

Hi all, I'm (26f) looking for advice but also to know weather I've been a complete asshole.

My younger sister (22f) was in an abusive relationship until around 6 months ago, during the relationship he didnt hit her but did other thing such as throwing things at her, giving her drugs and pretending they were part of her prescriptions, punching holes in walls/ doors and even smashing her windows. Eventually she went to the police and got a restraining order put out against him, ended things and seemed to be moving forward and healing.. that was until today.

I found out she has been in contact with him and even had him over at her house a few days ago. This whole time she has been avoiding contacting me saying shes having a bad period this month. Usually we speak daily but she has been avoiding me for just over a week now so today I messaged again, had no reply and decided to call as I was concerned. She opened up that she has been in contact with him, that she had him over and that she wants to work on things with him. Obviously I went into asking her side and what happened then explained why it just isnt a good idea; I reminded her of the things he has put her through such as the smashing up her home, screaming in her face, drugging her and throwing things, cheating, I even mentioned the fact he has started taking meth since they broke up. After talking this through with her she got very upset with me for 'bringing up the past' and told me he has changed and got clean, apparently he hasnt used for a couple of months but honestly I dont believe a word of it as I know he lies through his teeth to get what he wants.

After about 2 hours of talking I realised she has made her mind up here and I dont know how I'm supposed to help her, we arent in the same country and I did try to contact resources in her country for help to no avail.

This is where I may be the asshole; after we spoke and I'd realised her mind is made up I explained to her that while I'm here if she ever needs me, I can not sit and watch her go through this again. I have also been in an abusive relationship and it is beyond triggering for me to sit and listen to her praise an abuser like that. I also know I can not handle her calling me at all hours screaming and crying again as I'm absolutely useless in that situation and essentially had to sit and listen to the abuse happening as there isnt a way for me to contact the police in her country, she would have to do it herself but would call me instead. As you can imagine this is incredibly traumatic and frankly its terrifying sat not knowing if I were to be a witness to my own sisters abuse or at worst death if it had escalated that far. In my message I explained that I cant sit and watch that happen to her again, that I cant wait here faking happiness for her getting back with a man that ruined her life and mental wellbeing, I then sent her some domestic violence resources and told her to message me if theres any emergency or if she decides against the relayionship/ if she leaves him, gave a seperate number to message or call on and removed her from being able to message me on our main platform of communication.

I feel awful, like I have thrown her to the wolves but I really just can not handle it all over again, I had to seek mental health help after last time which I'm still in trying to process the things I witnessed happen to her, it was so traumatic I still have nightmares where I get a call telling me he went too far and she has died or watching him escalate from screaming and throwing punches at walls into him beating her to death while I'm sat helplessly on facetime unable to do anything. It has become my biggest fear and while I love her I have been told I need to put my own wellbeing first as she is an adult that will make these decisions with or without me. As a DV victim myself I know how hard it is to actually get out of these relationships though and I feel like a complete asshole for leaving her to go back.

Am i a complete asshole for leaving my sister to make this mistake? Could I have done anything else here and if so what? I love her so much, I dont want to see this happen to her and I'm so scared it will escalate further than before. Any advice would be great.