I had one of these and it ended up being just one of the many many reasons I eventually left. It was everything: open a letter and leave it and the envelope on the table, get scissors out, leave them out, clothes next to the laundry bin, dirty dishes on the counter above the dishwasher. The piece de resistance was taking off his boxers and socks in one movement and leaving them like an art installation on the bedroom floor.
I tried everything but if I said anything it was nagging.
When he retired he voluntarily started doing the dishwasher (I actually wanted him to share the cooking) and then I noticed that he started automatically putting his stuff in the dishwasher.
There were a couple of things about my ex that I think came into play. He hated, hated being told what to do. He had that perverse streak and would do the opposite in certain situations. He would buy me flowers too, but it was because he had decided to do it. He was only really happy in his work when he finally became the boss, and then went self employed so he could stay that way.
Secondly, he was one of those people that always had a million plans in his head. He was very goal orientated, always thinking about the next thing, the next hour, day, week.
He needed novelty and excitement. He got very bored by the mundane, the boring and the repetitive. He also got distracted very very easily. He would go upstairs for a shower and an hour later I would find him asleep on the bed. Oh yeah, he was lazy as well if it didn’t directly benefit him.
So if he was opening a letter, the letter would remind him he needed to send an email, so he’d send the email and leave the letter and envelope wherever. If he was getting dressed, he’d be thinking about what he was doing next, so clothes left on the floor, because his mind was already on the next (very important) activity. DIY jobs got started but never finished - especially if the task took longer than anticipated or was more difficult, or just became boring.
It felt like he had a butterfly mind., but also he didn’t really think I was his equal. He would have said I was, but he actually didn’t think anyone was his equal I suspect. He could pay attention and focus, but it was only if he was doing something he liked.
Funny enough when I go back to my old house where he is still living, it looks neat and tidy.
If I had a solution, I would offer it up, but you said you wanted to understand why he does it.