@Ernest BywaterTrue enough, but I was trying to do the first pass as mostly true autobiography, and then go back to insert the do-overs.
UPDATE
Some of my fellow authors may have gotten the wrong idea, in that I'm looking, at the moment, at great social or technical changes.
Nah. Personal events, mostly with real women in my life. Some of the alternate paths are my own thinking, some of them are things examined in deep and effective psychotherapy, and some are based on things I've learned fairly recently, such as why ex-#2 did certain things.
One thing, for example, that was brought up in therapy, a somewhat suppressed memory (no, I'm not talking about repression in the McMartin preschool scandal). I had started working out in a hard-core gym, for tension relief and physical fitness. I introduced my then second wife to it. She became compulsive about training for amateur competition bodybuilding, got a vampirish female training partner when I didn't want to work out 6 days per week, and, to a significant extent, shut me out of her life. With my therapist, in part using EMDR therapy, I realized that period made me start avoiding my own fitness activities.
Lesser fitness also had other negative physical consequences. My staying with the exercise, with her or not, could have affected a lot of things downstream.
Both before and after, I discovered some female friends and colleagues were interested in me, in a manner that would have been OK in our open marriage. I just didn't pick it up.
One is kind of funny. A very smart fellow engineer, it turned out, was a NFL cheerleader and occasional runway model on weekends -- and one of the sweetest, most supportive people you could meet. Later on, when we both worked elsewhere, I was teaching an engineering class on the road, as was another mutual friend. She thought she signed up for my section, presented at a motel just off the beach in Tampa, but was my other colleague's section. He told me that she routinely showed up in bikini under a coverup. A third mutual friend told me she had wanted some private time with me, and had gotten clearance from my wife, in whom she also was interested. I was oblivious to it all.