Wow, I'm really impressed by all the insights you've been having about how your childhood impacted your adult self, and ways in which you now know you need to grow. And it's really good that you're not beating yourself up about it, but rather accepting that although there's no way to change (or therefore regret) past choices, you can change yourself NOW. In my opinion, that's one of the most important lessons which people learn here, and it's always awesome to watch someone discovering their strengths and making changes which they can take pride in (and which will positively impact their children). So, well done, you!
About the OW, try not to waste time thinking that she is less "damaged" than you. For one thing, it's all speculation or projection, or one of those kinds of "disordered thinking" that we're warned about because we're substituting them for reality.
For another, from what I've read, OW are never less damaged--they're just damaged in different ways. For one thing, no emotionally healthy woman would get involved with a married man. For another, depressed men do not seek out partners who are in a better space than they are: they are attracted to the same negative energies in the OW that they feel in themselves.
In my H's case, he seemed to be attracted to the OW's anger, jealousy of those who were more successful, blaming others, and above all to her need to be rescued. Often, the OW is even a substitute for the mother who rejected or hit or otherwise abused them--a desperate attempt to fix that type of relationship. In the end, of course, the MLCer has to accept that the past is past and work on its effects on himself, just as you are doing.
