Poor Boundaries When it Comes to Flirting and Other Women

This is my first post, and to be honest, I'm ready to pack my bags after eight years with my ADHD boyfriend. 

He has always been pretty oblivious to his own actions around women and even early in our relationship, would get distracted by other women and unconsciously flirt with them, while COMPLETELY ignoring me. I never dated a guy that did that so I was somewhat amused but also annoyed, but I didn't see it as the red flag that it is. Or really, after more heightened instances of this, we would fight, he would do a charade of mopping, and then we would resume our tedious lives together. Is all of this disrespectful behavior even ADHD? The ADHD spouse group I am in says yes. 

Yesterday, he trained a woman that I actually work at my own place in a job that he works on the side to supplement his woodworking income. I am friends with this woman but I don't know her well, we are just friendly at work and then she joined me and him for some food and drinks after an event last week. Anyway, they spent the day together driving around so that he could show her what the everyday tasks were like. After, they drove back to where she had originally parked that morning and they decided to get dinner. He called me last minute to see if I could join but I still had to walk the dog and get ready, and the drive was still 20 minutes away. Since I am in the midst of applying for grad school, I decided to stay home. 

Since he's just alone with her and also bringing me home food, I assume he'll be home in a relatively reasonable time. He ends up calling me almost three hour later, and then comes home thinking it was perfectly fine to have a long and leisurely dinner with drinks with my female coworker without me. And he probably paid because he's inclined to do so, so essentially they went on a date. I briefly told him how inappropriate it was on both of their parts and he made a bunch of excuses while also apologizing. What angers me is that his choices show such a deep lack of respect for our relationship. Like, an hour together tops is fine, but almost three hours? Honestly, I'm so disgusted by his lack of judgment and I don't even know what to think about my friend - who was also married at one point and should know better. I eventually made him sleep on the couch though he was sleeping peacefully before that like I hadn't just yelled at him when he got him. 

I don't trust him, mostly because he's demonstrated poor judgement in the past in regard to making decisions that either pulled him further into compromising scenarios or not. I know the dinner was entirely innocent but months of long days together and three hour dinners here and there is exactly how affairs begin. I almost can't believe how foolish he is except that I know him and have seen him gravitate towards specific women in our friend groups like they are playing the flute.

I feel like I'm living with a 15-year-old boy. He didn't even fully understand when I explained to him just how inappropriate it was. They probably spent 11 hours together in total. And even today, he said that he was sorry but he really needs help with his side business and that she has the specific training he hasn't been able to find for years. While that is true, its just another layer of respect for me. I'm so hurt but I'm also done with us because, as you can imagine, there are many, many other serious parts of our relationship that are really problematic. I am trapped right now due to finances so I don't know if maybe I can sleep in the living room till I can move out. The only reason I haven't broken up with him in the past is that my family is abusive and I don't have them to help me through a transition away from him.