3 year relationship. Both 73. Lives are entwined. In arguments consistently and he keeps telling me that I am the problem. We get along in some ways, but end up in an argument. I tried, but no solution. Should I cut back, or should leave him?

With your ages in mind I would have to onder if there is something medical causing the problem. Often times in the beginning of dementia the person will show anger over fear, or weakness. Carefully assess your partner and if need be get them to see a doctor.

If that is not it than I would limit your time and also talk calmly when you aren't arguing about a way to get past it. If not then walk away. There is no reason to live with the stress.