You know your cat best, if you don't feel you want to look for a sanctuary then PTS is the option. However I have a little story...
I adopted a damaged cat, didn't know at the time that he was a bit of a problem but once he was 'home' it was too late. I had taken him and he needed someone to love him. I loved him.
He would attack me, every day as part of his routine he would go for my ankles and bite, play fight. He would ambush me in the garden and always go for my ankles. If he was in a weird mood he would also jump at my head. I learned how to deal with him and was always careful around him although sometimes was lax and it resulted in an injury of some kind, only once did I need medical treatment and that was my fault really.
No way would he have been OK with children, although most of the time he was great, a normal cat, loved cuddles, laps, but had been a farm cat we think, badly treated and injured so could turn instantly and attack.
Almost 11 years he was with us, I adored him, he was my friend. BUT there were times when I was afraid I wouldn't be able to cope, not down to him, just my life, and I knew it would be wise to make provision in case something happened and he needed to be rehomed.
I found him a home for life, to live out his days should something happen to me. I knew he would be cared for, as were all the other unhomeable pets, for the rest of his life. I never needed to give him up, he grew old with me, eventually the day came to say goodbye and he went to the vet for the last time, but it was made easier knowing that there was someone out there that would have taken him in and given him love in spite of his problems.
He was old, he was unpredictable, he also wanted to be alive until the day he just looked at me and I knew he was ready to go. I felt it was right. However, my other cat was not ready, even though she was ill, and I will always regret not giving her those last few days of love that she fought for.