Is hope dangerous?

Just when I thought things were going great, the proverbial shit hits the fan. We have been getting along really well and I started to let down my guard and feel loved by my husband. Big mistake.

ok, the story. My husband had to move my dryer some time ago to put in plumbing for a sink. In its new position it cannot be vented to the outside, so the lint flies freely around the house. I asked him to put a nylon on the end, but he is afraid it will start a fire. I asked him to put a new hole in the wall, but he doesn't want to do that because we want to move the laundry room to the second floor one day(!) so why put a hole in the wall for nothing? A few days ago I mentioned that the lint causes me pain in my sinuses and the dirt is relentless. I asked him if we could just move forward and move the washer and dryer. He said" let's do it Monday when you have off". I was ecstatic! 

So this evening I asked him if we have everything we need, or do we need to run to Lowes in the morning. He said we have everything. I asked him if we had a pan to go underneath the washer, in case it leaks. That's when I realized he had no idea what I was talking about. 

It turns out, he thought he agreed to pulling the dryer forward by 4-5 inches and fishing a hole to the original site. I told him I wasn't comfortable with this because the dryer will block the doorway to the only bathroom my wheelchair bound brother can use in our house. I tried to be reasonable, if moving the washer and dryer upstairs was not in the cards could he just cut a new hole in the wall. He reiterated the previous argument about putting a hole in the wall for nothing. He promised that if my brother was coming he would move the dryer. The problem is my husband works every weekend and weekends are usually the only time I get to see him. I told him I didn't want to be put in a position where I would have to tell my brother he can't come because he called too late for me to get my husband to move the dryer. Why are things this complicated!!!

So my husband gets a little indignant, like I shouldn't be concerned about him moving the dryer, and besides he says I thought we agreed that this is what we were going to do. My head is spinning now. We have had this discussion numerous times, I NEVER agreed to the I'll move it before your brother comes plan. I just think it is ridiculous. Who lives like this? But I DIDN'T SAY THIS! I just calmly told him that I don't remember that being the case.  So he says " well, I guess I'm the asshole then!"

​I told him I don't think he is an asshole and it bothered me that he would put words in my mouth. So he says, I think we should split. At this point I am just beside myself. I asked him how he could threaten to leave me over something like this. ( background, this is is favorite ploy, which I have said must stop. We are either married, or we are not. Threatening to leave is not healthy.) I got angry and raised my voice, so he told me he is tired of being yelled at. I pointed out that I only raised my voice after he threatened to leave me, but he insisted that I was yelling the whole time. 

​At one point he told me I only care about myself and his feelings don't matter. I actually started to cry at that point. I asked him how he could say something like that when I spend so much time trying to educate myself about his ADHD and trying to understand how he thinks and feels. His response? " you do that stuff for yourself". I am totally at a loss at this point. When I tried to explain, to defend myself, he again says I think we should split. I mean I just can't believe how things have escalated. He goes from zero to sixty within minutes.

at one point, he actually said that his comment about him being an asshole was meant in the most magnanimous way! He was trying to give me the upper hand, be generous at admitting fault. He believes anyone would see it that way, and I'm not thinking clearly. I even tried to go along a little and said, even so, I don't want to be given credit for calling you an asshole, or even thinking it, because I wasn't.

he ended up leaving. He came back a little while later, but I am just dumbfounded! He keeps talking about how he just doesn't want the conflict anymore. As far as I can see, he is the one who launches a simple problem into a life altering one. Am I wrong? Shouldn't spouses be able to disagree about something like this without it turning into ww3?