After Years, abrupt break up and no communication by ADHD SO

Hello all, long time lurker here but first time poster. Up until a few weeks ago I was in a relationship for 5 years. The individual had been diagnosed with ADHD since they were a child. They were on meds but about a few months ago the medication stopped being as effective. Our 5 years together were great (not the first 2 years but the rest was). Or so I thought. Lately we had been going back and forth about progress in our relationship. After 5 years I was looking to get engaged and move in together. We had lived together informally for short periods before (during life transitions, apartment changes, etc.) and it was amazing. Throughout this relationship I was always proactive about reading about ADHD and researching various aspects and trying to make sure I was understanding what was happening. He would even joke that he felt like I understood it better than he did (of course not true since it is his personal experience).

Initially he was on board with the engagement and then this changed. He didn't want to discuss the topic. It coincided with his general anxiety building about changes at work and in his personal life. I was at fault because I kept pushing the discussion and instead should have respected him and given him space to figure out what was happening internally. At first I gave him space but then I brought it back up because it was important to me, I felt as though we were stuck in one spot since year 2. Over the past year he had a lot of built up anxiety and the meds weren't really working anymore. He asked me to help finding a professional in our current city so I researched and found a good psychiatrist and therapist in our city but it took him months to get around to seeing them.   I was feeling like...if the issue for us to move forward is X, shouldn't we try and work on X? I wasn't very understanding. 

But it is not as though we were fighting all the time. Our first two years were tough due to cheating on his end and we got into a bad cycle with arguments and such for a while there. I was unkind for the 1.5 year post-revelation. I wish I had been less cruel/mean in our fights after that. But when I made the decision into year 2-3 to forgive him and forget about it and never bring it up because he had truly evolved from that person who cheated on me, things got a lot better. However, he couldn't see me as a person who had changed. He constantly said that he was really afraid of us fighting and still saw me as that angry person even though he knew I was no longer. We have had amazing trips around the world, my family has accepted and loved him unconditionally, and we had built a cozy corner of the world for just the two of us. We saw each other every day. I helped him apply to jobs, edit even the most minor emails and texts if he asked me to (for example maybe edit email tone for upper management or something). We trusted each other's judgment a lot. 

We had an argument one evening a few weeks ago (mentioned above). I regretted my tone immediately and tried getting a hold of him to no avail. I definitely overdid my attempts to get a hold of him. The next day I received a text that basically said while we love each other we are bad for each other and we make each other unhealthy and I cannot contact him anymore and he can't see me and that while he will hold the memories dear this is it. He said he was really struggling psychologically and emotionally. Then he promptly blocked me on everything. His mom texted my mom and said the same exactly thing and said that we both need to focus on healing and getting healthy. We are approaching 30 (age wise). 

So, I guess I am now in a place where 5 years ended over a text. The dreams of us together and the 3 kids he wanted and the 2 dogs and the trips we had planned....all gone. My best friend, the closest, nearest, and dearest, my person who just got me and whom I held and loved unconditionally is gone. Yes, we had the usual procrastination issues in our relationship that led me to pick up the slack 70% of the time BUT I was happy to do it. Sometimes I would mention to him that I was in a place where I needed extra help but usually it was fine.

Can it truly be so final? That he will never reach out again even to just say hello or be friends or have a conversation about what went down? I don't really understand what happened. Why couldn't the end at least have been a conversation? I am in a lot of pain. Weeks later and I am still hurting very much. We loved each other very much. I have given him the space he asked for and have not reached out. I just can't accept that the years were so terrible and that we were in a downward spiral especially since just a month ago he had told me that this past year was amazing and our best yet. I will have to get in touch in a month or so because a lot of my personal belongings of great sentimental value are at his place but I might just have a neutral party do that so he doesn't feel like I am disrespecting his wishes. 

I both want to respect his wishes but I also want to in a month try reaching out to say hello and ask how he is doing. No other questions. It'a tough to be so out of the loop on his health. 

Has anyone out there gone through this? Perspective of folks with ADHD, have you ever ended things abruptly and then changed your mind? I don't understanding not letting me even say a word.