Well, I’m going to give you somewhat odd advice. I’m looking from the perspective of, firstly, a man, secondly, a person who has the same type of problem as your husband.
My room (I don’t own a house) is not a pigsty. There isn’t really filth unless visible dust or a 0-1 days old coffee cup counts as such. But there is little tidiness otherwise. You will find a Harvard Law Review article with marginal notes (in pencil), tossed on a history book lying on an air humidifier placed on top of a chair under which a psychology magazine fell a couple of days ago, not far away from a military style belt, a yard away from my desk, featuring a couple of such things as a tube of thermal compound and some other stuff used in tinkering with computer hardware, a photo camera with spare batteries and some medications (religious articles are in a state closer to order), some Lord of the Rings correspondence and a WWF postcard. This all gives the imaginary beholder, a cross-section view into my life and what kind of person I am, including messy. But there’s much more to it than messy (which is a fault), isn’t there? I suppose “messy” wouldn’t be the major focus after a while looking at those things and thinking about their owner.
When I leave something somewhere, I expect it to be there. In fact, if it were to be relocated neatly, I would probably end up unable to find it, which could wreck my desperate, last-minute excuse of a plan or schedule. Even when it is an empty coffee cup, I do not leave it for anyone to pick it up. I expect to pick it up myself, just
later or
not at this time. I respect the sensibilities of the more orderly people but I’d be grateful if they’d understand me and not e.g. interrupt me in the middle of work or rest to remind me of, say, an empty cup I managed to forget about in the kitchen while leaving in a hurry or when the phone rang in the other room and then something else happened. (Just please ignore it or ask me to pick it up when you sense a moment I’m not busy or tired, and omit the lecture, and this will make me thankful and perhaps I’ll apologise or make a mental note or something.)
Also, frankly, my memory is limited in a number of ways, as is my attention span. I need to cut some things. For some things I simply don’t have enough time due to, yeah, deficient planning (e.g. I miscalculated the time left, looks like I have to be leaving right now, can’t clean up, I own the mess but I can’t clean it up
right now). Sometimes my mind is in a different land when I have some particularly absorbing, abstract stuff to think about and it literally hurts physically from the mental tension. A stray empty cup or box or bottle may fall victim of that. I
don’t intend to have anyone else clean it after me. I wouldn’t mind being asked to do some major cleaning in return for my transgressions. But I can’t reprogram my mind to appreciate the gravity of real-time tidying. I do believe that as long as the cups etc. are mine and I own up to them and the duty to clean or tidy them up
at some point (especially if they are on “my turf”, where “my turf” doesn’t mean I deny it being part of a common space, it’s just that nobody else is really forced to keep order there), I am not doing anything objectively wrong in a major degree. I can’t help my brain forgetting the empty coffee cup due to regarding it as trivial next to some project at work or even some kind of non-work intellectual exploration I’ve just embarked on. This absolutely does not mean I disrespect any person who may have a problem with it or feel compelled to wash that cup I left (with or without addressing me about it). In fact, I’d probably brew and wash both cups if I had someone from family or friends around to keep me company with the coffee.
Anyway, I guess it’s time for a summary of this longish narrative. Please resist crediting the messy person with leaving the mess for other people to clean. This isn’t necessary how a messy person thinks (although some may do). Please make room for such things as poor memory (long-term or short-term) or even the fact that someone with a poor memory isn’t really longing to train his or her memory painstakingly or try to reprogram his attention span, just for the purpose of no more failing to pick everything, always, fast enough, neat enough, especially considering that he or she may be attaching a different weight to maintaining constant orderliness. Sometimes, actually, I’m a little sad for people who put so much emphasis on bringing things to a perfect order. I really wish they could put it down for a while, sit down, get a coffee. Sometimes I try to teach them to. It can be heart-rending how they overwork themselves, denying themselves joy. You (the Opening Poster) don’t seem to be there but, anyway, please be careful.
(TBC)
:clapping:
). We have bins for things and “zones”. The kitchen and bathrooms are germ-free,so a stack of newspapers on the floor, or unmade beds don’t get a second glance around here. 
I’ve only just noticed the part about the pocket knife and about his response to you (“you’re going to hate it anyway”). The part about pocket knife needs addressing. Dangerous objects just need to be handled safely. The response can’t be one thing to base a judgement on but it looks hostile and filled with resentment. There may be some bigger problem bottling up, even though “normal people” can be rude too when confronted with their shortcomings. It sounds out of character for him, from the way you describe him.