Dutchman, I'm so sorry for what you are going through. It's one of the toughest things.
When my husband was in the nursing home, I made a point of never wearing a coat or carrying a bag when I went in. I left them in the car. That way, when it came to leaving, there was no visual clues that I was, actually, leaving. I would tell him simply that I had a couple of things to do, and say "I'll see you later." Time had no meaning for him anymore. At one stage, after I had major surgery, I didn't get to go in to visit for four or five days. I sent relatives in, to collect laundry and check on him. He never asked about me, or missed me at all. And when I did go back in, he greeted me exactly the same as he always did.
He also came to believe that when I wasn't with him, I was busy around the nursing home. He thought I lived there too, because it had become "home". It's really hard, and I'm sure all of us have been tempted, once the daily stress and sheer exhausting work of caring at home is no longer there, to look back with slightly rose tinted glasses, and think that, really, things can't have been as bad as we think. That's why it's really useful to be able to look back over our posts and see our own words telling how horrific it was. In fact, after my husband settled in to the nursing home, we had a restored quality of relationship that hadn't been possible for years. We were able to just relax together, while someone else took on the actual work of care. This benefitted both of us, because all of his aggression was centred, generally, around personal care. I no longer needed to deal with that, so he became more relaxed around me.
I wish you well. And I hope that you will allow yourself to get plenty of rest, and some restorative time doing other things between your visits to your wife's care home.