TD - what I’m trying to say is that you never met the right one. Your WGF was never the right one. If she were the right one, she would have moved heaven and earth to R. You yourself said that the entire female side of her family cheated and the only reason R occurred is due to rug sweeping. Your WGF possessed a major defect from the get go.
Your WGF entered the relationship with you with a distorted view of fidelity. This was ingrained in her by her family experience. You were thus sitting on an infidelity ticking time bomb.
Her cheating wasn’t an opportunistic event, an exit A, a lost in the fog situation, she didn’t accidentally fall into it. Her calculus was that whether she would be caught or not really didn’t matter. Cheating was her right and you would fall right in line and move past it. Her A was inevitable snd pre ordained. She was that person 25 years ago and is that person today.
With this mindset 25 years was good times, shared moments, family, friends, kids, intertwined lives, good sex, That’s what you experienced. Her take was a bit different no doubt because her experience included all of these things plus an innate right to have an A. Thus, part of what you experienced was an illusion.
It’s absolutely inevitable that you will eventually find someone better. The most significant character flaw a partner can have in a relationship is the willingness to cheat. Your WGF is fairly unique in that her cheating was inevitable. You saw all of her cheating female family members and thought that your WGF was going to be different. Perhaps it was cognitive dissonance.
You will find the right one when you find most, if not all, of the qualities you liked about WGF plus the one most important attribute she lacked - a moral core. Isn’t a moral core the most important attribute for any human being? You can and will do better my friend, but not until you stop comparing your dates to a false benchmark, re your WGF.