How do I stop trying to help my disrespectful, lying, narcissistic father and leave gracefully?

My 79+ yo father has always been self centered, rude and disrespectful. But the past 6 weeks have pushed me too far. His disabled, long time partner got ill and died from Covid. He brought the virus home to her, disregarding wearing a mask or using any precautions. This is the same man that was so selfish 15+ years ago when he refused to do the right thing and “let her go” after a horrible car accident. She spent all those years unable to stand, walk, bath, dress, etc. on her own. Always had to have a caregiver and sentenced to a miserable life in a wheelchair.

He, of course, calls me upset when she is taken to the hospital for illness. Only after she was intubated and tested positive for Covid did we realize the severity. He went to the hospital coughing, sneezing, not wearing a mask. Finally, had to be asked not to come because he was exposing everyone there to possible illness.

After his symptoms improve and minimum days pass, I travel across the country to help. At first she improved, but then took a sudden downturn. During this time, he insists on moving as he has not been happy for 2+ years. He tried to move on his own but could not get this done. I wanted him to slow down and just settle a bit. He persists and begs me “not to leave him there”. So, we settle a few things, pack his stuff and list the house. About 1/2 the way to his desired destination, he changes his mind. All the while, his phone, which he can’t hear well, is continually ringing. He is elusive about what is going on…..

After a short detour so I can reset at home, I was gone far longer than expected, we were to discuss what he really wanted to do. He insists on returning home…..the next day. I am unable to accommodate quite so quickly. We have a discussion about why, he has no answer. I told him I knew about the affairs and did not understand what he was doing. He denied it all….. liar. I called the mystery woman, she denied everything of course. I told him if he could not be truthful, he could stay in a hotel nearby until I could make arrangements for him to get home. He left the next day, going to drive himself home…1,800 miles. Called police and tracked him down. He did ok until I got a call from the police in another state. They were not going to let him drive, unsafe and confused.

Got him back home, but house sold. I spend 2 more weeks finding a place for him to live, arrange move and unpack. Fix up apartment. Take care of mail fraud issue, get taxes to the right place, changing addresses, took him to PCP to find out what was going on with him and called an attorney. In the midst of this, we reset his phone and voicemail as it was full for a year. Of course, much younger, lying girlfriend left voicemail and text messages asking for money and “love”. Tried to manage this to settle down the calls at all hours of the night. Worked for a short while, but she got a new, unlisted number. Made contact again. I found more recent calls and texts. I called him out, lied to my face again. Called her out again, finally admitted she “was in love with him for years”. Really?? A former caregiver of his partner and much younger…. highly suspicious of her motives. And his despicable cheating and lying…. never been committed or faithful to anyone. Why all the secrecy and sneaking and lying? He finally admitted there was a relationship, but “was no one else’s business”.

I have given much to this man over the years. Helped when he had MI, when he had problems after partner's accident, moving him more than 1 time, listening and visiting regularly. He has been mean, belittling and disrespectful for most of my life. He has no relationship with my other siblings, he just does not really care.

I feel he has some cognitive changes, won’t acknowledge or address. I am his springing POA, but am ready to walk away….. am I off base here? Can I leave now? I just can’t deal with repeated lying or justify his sham “relationship”.