So your partner lived with you for six years, but kept his own house on as well. He paid council tax for his other house, so was basically registered as living there - not with you.
He kept you separate from his birth family and his adult children, despite knowing this upset you.
Did he get mail at the other house? It sounds as though he was keeping your relationship secret and separate from his other life. Like a married man hides his mistress. This would make anybody feel insecure.
He had been telling you you were unbalanced for a long time.
He took advantage of your septic cut to tell the GP, who was a locum and therefore didn't know you, that were irrational and had "psychedelic dreams", whatever the fuck those are supposed to be.
As you'd been having yet another row about his keeping you away from his family - and were, very likely, feverish due to the infection - you blurted your emotional problems out to the locum. Who took this to be evidence that your boyfriend was correct about your "instability" and began mental health procedures.
After you were sectioned, your boyfriend visited you in hospital where he ignored your complaints about your treatment, instead persisting with a fiction of gentle therapies which you were not receiving.
Did he register a formal complaint with the police about their handling you with undue force?
Why was he not present when you were sectioned? Assuming he instigated it, in his "caring" role, he must have known when it was scheduled.
Did he look after the dog while you were in hospital?
Why did he not take care of your home? Why did he not fix the doors, apparently breaking in to retrieve his things instead? Why is he now talking to you about "rest homes" like something out of a Victorian novel?
It looks to me as though he engineered your mistreatment. What do you think? Have I misunderstood what you wrote?