If you don't want to forgive...then don't.  Some things are unforgivable.  My own flesh and blood abused my DS18 and covered it up for 2.5 years.  I haven't talked to my 'brother' for the last 2.5 years and my own 'mother' for about 1.5 years.

Some things are just too f*cked up.  I don't blame you OP - I feel the same.

I forgive for myself, but I don't forget. I had a SUPER close friend in college. She had severe anxiety and depression. I can't even tell you how many times I missed work or class because she was having a severe attack and I wasn't leaving her alone. How often I left things if she managed to message me and saying she needed help. She got checked into a facitity for care. It was great for her. I wrote her once while she was there, lots of personal crap flared up for me at that time, so I relaxed constant contact, because to me, she was safe right now. When she got out, she informed me I was toxic, that I ruin everything and had never been there for her, and that we were no longer going to be friends. Obviously all bull. But I cut ties. Since then i've spoken to her once, she apologized, I accepted, but that didn't "fix" it. We aren't friends anymore. We don't chat. Becuase I didn't need the drama she created.

That being said. That was MINOR compared to C'tucky... So no. I don't think you're overreacting. I think you're being reasonable and I'd likely act the same in that situation.

Sorry, but IMO, but 6 months is not long enough to guarantee Ssis has truly turned herself around. Allow me to tell you a horror story...

One of my closest friends has a younger brother who has been a trainwreck since he was a teenager and has abused drugs and alcohol for over 25 years.He got his shizzit together long enough to marry and have two beautiful daughters. And then he fell off the wagon. He got drunk and beat up his wife. When he sobered up, he promised to get help and get better. It lasted less than a year. That time, she needed stitches. It was the final straw for her and she filed for divorce.

He jumped back on the wagon and got supervised custody of his daughters. Things were going so well that he was allowed short, unsupervised visitation and overnights were under consideration. Until the day he showed up early to drop off his girls and was obviously under the influence fo SOMETHING. Both girls were in the car, bawling. He opened the car door and screamed for them go "GTFO of my GD car". The youngest didn't move fast enough for him and he grabbed her by the arm, dragged her out of the car and THREW her towards her mother. That poor baby had to have gravel picked out of her knees. Aaaaand he lost ALL rights to his children.

Once again, he got clean. The other brother took him in and found him a job. As soon as he got his first paycheck, he disappeared on a bender. Showed up at the house, still under the influence of booze/drugs and tried to FIGHT with his brother (who is built like a freaking linebacker). The police were called and he went back to jail.

When he got out of jail, he was bouncing between the couches of friends and homeless shelters. He held down a job for 5 months and asked his sister (my friend) if he could stay with her. She said yes. Things were going well for 2 months. Until the night my friend awoke to screaming and raced into her daughter's bedroom to find her brother trying to rape his own niece. She was fighting to get him off of her daughter and he punched her in the mouth and knocked out one of her teeth. Her youngest son (15 and BIG) came flying into the room, pulled his uncle off of his sister and literally had to knock him out. He was arrrested and spent 4 months in jail.

When he got out of jail, he was once again living in homeless shelters or staying with friends. Another job, another few weeks of things going well. And another binge. He went to my friend's house in the middle of the night, broke in, and once again attacked her daughter - his niece. And again, her 15yo brother came to her rescue. The daughter spent 2 days in the hospital and her uncle spent 10 months in jail.

He claims he has found Jesus. He has been sober for 6 months. Only time will tell. In the meantime, his brother, his children, his exwife, and all of his nieces and nephews refuse to have anything to do with him. Only my friend, who is eternally hopeful.

So. In NO way do I think you're out of your mind. I completely understand why anyone would be hesitant to welcome her back with open arms. It has not been long enough for her to prove that this "change" is legit.

Oh god no, once I go scorched earth on someone that is IT. 

6 months isn’t long enough to turn any kind of corner.. Maybe 5-10 years of consistent improvement with no relapses and I’d consider that she’d actually changed her ways. But she wouldn’t be getting an invite back into my life, ever.

Toxic, abusive people do not need to be welcomed back, and you’re not missing anything. The hopeful, trusting people are missing the fact that toxic horrible people should never be trusted. 

I wouldnt just let it go. Honestly if theres been a pattern of behavior (not just a one off stupid choice or mistake) I'm pretty much done with that person whether they've "changed" or not. It's just too rare that someone has actually permanently changed. I dont really get why other people seem so eager to just put things in the past and believe the person is different now.

Ss34 could become a paragon of virtue, but he will never be back in my life.  I don’t actively hate him - he’s not worth the effort.   He’s just a nothing to me.

 There are lots of people that have passed thru my life.  No one can keep up with everyone they have ever met. Just keep the ones you want to keep.