Have others have experienced anything like this? Abandoned for affair

I'll try not to go into too much detail because it's been such a wild ride I could easily write a novela about what I've experienced. I will preface to say that I do not think this is all because my former partner has ADHD but I question if the way this all started was due in large part to his ADHD, whether anyone else has experienced anything similar and if my gut is right about what I might expect to come in the future.

My partner and I were together for 8 years and I had started to suspect he had ADHD, which was later confirmed by his mother, but we had not made treatment a priority yet (after reading the book oh how I wish we had). Our relationship was not perfect by any means but it wasn't terrible. We had the usual pattern of arguments related to household chores, finances and me feeling like he didn't show enough interest in me vs things he hyperfocused on and we had discussed trying therapy when we could afford it but for the most part we were ok with occasional arguments when one of these areas would really flare up. He went on a trip for work that involved traveling out of state doing electrical work with a crew of guys and was gone for about 5 days, during which time he would text me daily and called me every night before bed. He complained about wishing he was home, said he missed me, that he loved me and even made a suggestion for a vacation we should take. When he finally did come home he didn't tell me he was coming back that day, which was unusual, so I was surprised when he suddenly came home. He seemed upset but from how poorly he said his fellow crew members behaved and overall how badly the trip went I assumed he was just tired and frustrated about that. He immediately went out to smoke and then came back in and said he had to tell me something. He had met a man who offered to fast track his career and promote him quickly if he moved to this other state. He wanted to break up and said he didn't love me anymore and hadn't for a while and we'd both be better off. He spent a lot of time telling me how wonderful I was and how I deserved someone who could give me all the things he couldn't and make me happy. He didn't want to try long distance and he didn't want to work on things with me because there was too much baggage and it would be too hard and take too long. He would be leaving ASAP for this promotion and it could be as early as a week but it would be by the end of the month at the latest. Long story short he stayed for 2 months and was very back and forth towards me the entire time, at one point flat out saying he wasn't sure if he wanted to leave or not and other times saying that maybe we could try again in a year when we were "both better people." He denied multiple times that there was another woman but was really awful at hiding it so my suspicion was high even though I didn't want to believe it. He finally did leave when I demanded he pay me at least part of what he owed me for rent because he had continued saying he was leaving ASAP only to go on two weekend long trips supposedly related to this wild job offer where he spent obscene amounts of money and then was effectively broke until his next paycheck and couldn't give me anything towards rent. He blew up at me when I demanded rent and seemed shocked when I finally drew a line in the sand but did leave the following weekend. He claimed this was planned but then told me he was living out of his truck for a short period when he would still call and text on occasionly.

Finally the communication went silent and I confirmed via checking phone records that there had been another woman. The thing that I still can't wrap my head around is that if the phone records are correct he met her the night before he came home and broke up with me. It never appeared on any previous phone records and his behavior prior to that time vs after was very different to where it was obvious to me he was focusing on someone else. After obsessively reading about affairs, ADHD and various other topics my best guess is something involving the impulsivity of ADHD potentially mixed with extreme guilt and shame after probably getting drunk and cheating in what should've been just a one night stand that he couldn't bear to admit to.

He went no contact for a few months and then had reached out to me in the spring. We texted throughout the work day every week day for two months and he went so far as to switch to email when his service was shut off to his phone (he never really did figure out budgeting on his own). During these conversations he said he was unhappy there but danced around the topic of being in a new relationship. He started to talk about wanting to come back to our city and told me about jobs he was applying and interviewing for. I finally confronted him and called him out on the other woman and said I was willing to work on things with him if he wanted to come back but I wouldn't chase him and I wouldn't beg. I told him I was incredibly hurt but I didn't hate him and I've learned a lot about our relationship and infidelity as a whole and now believe it is something we could rebuild a new and better relationship from. He said he realized he had made a mistake leaving and listed off the ways that I outshone this other person. I asked how they met and he told me it was a random person at a bar just as I suspected. He said he thought he wanted to come back but was afraid that he would hurt me again or watse my time if he changed his mind again. He finally did say this is what I want and these are the steps I'm taking to come back, followed by a call in the middle of the night later that week saying the opposite. I was also treated to a few emails and texts from the affair partner first telling me to not contact him again and then begging to know whether our communications were platonic, neither of which I responded to. I haven't heard from him in a couple of months now and I have reason to believe they've finally gotten an apartment together (they were living with her mother prior to this) but he still has not taken himself off our lease and still has keys and a garage remote he left with and has left many of his personal belongings here. I know part of that could be the ADHD forgetfulness but part of me thinks it's to avoid fully severing all connections to me.

I can't wrap my head around why he is still staying there given everything he told me about what's been going on and what all he was unsatisfied with (both how controlling she is and his new career prospects) but my gut tells me I'm going to hear from him again and it potentially could be in the form of him just showing up one day. I'm back to being on the fence about what I would want and whether I'm willing to try again if he's genuinely remorseful if and when he contacts me again. I'm doing my best to try to focus on myself and moving on but it's hard to shut off the nagging feeling that says something else is going to happen. It's partly wishful thinking on my part but also partly knowing him so well and knowing based on the things he said when he reached out that he does still have feelings for me and he does have remorse/regrets.

Has anyone else experienced anything like this with an ADHD spouse who not only has an affair but essentially abandoned you for the affair partner when they hadn't actually even known the person long enough to form any kind of emotional attachment and it was likely impulsivity and the thrill of something new and exciting that led then to take off? If so did they eventually try to come back? Or for anyone who in general has experienced their spouse leaving for an affair partner who then eventually tried to come back, how long did that take? What did you do? Should I just sell the rights to the story to Hollywood and cut my losses? Mostly joking on that last one but if anyone knows a good screen writer hit me up ;)