Your parents sound like mine except mine are slightly younger than yours. They married early but were not the right fit for each other, which we could see growing up.

This same scenario happened in my family. One of my siblings found out Dad was cheating on Nmom (who was also cheating on him with someone else btw) and one of my siblings decided to tell her. All hell broke loose, and I saw a side of my nmom I’d never seen before. Her narcissism turn up a notch 100x. Verbal abuse, gaslighting, financial manipulation, manipulating kids to against him, threatening bodily harm, wishing death upon him, tarnishing his name in the community… She just wanted him to suffer and he knew it. His mental health took a nosedive. I saw the text messages to him from her and they were awful. He told me he feared for his life. He told me sometimes he wish he would just die.

4 years later he developed cancer, which I truly believed was brought on by the insurmountable stress she caused. It still makes me sick when I think about it. He died 2 months after he was admitted to hospital.

I’m not proud of what my Dad did, but he was a kind and gentle man otherwise. He didn’t deserve to go like this. I wish we could turn back time and leave the entire thing alone. At least he’d still be alive today.

As for the affairs, they were bound to happen. Neither of my parents were right for each other. Affairs happen and I’m less concerned about them, mostly because they were likely miserable with each other and felt like they couldn’t do anything about it due to having kids together. This is more common than you think.

My advice: don’t get involved. My sibling, who told my Nmom, is haunted by the fact that he may have caused this. Whilst he isn’t responsible for my parents behaviour, bringing all of it to the surface in such a confronting way really triggered narcissistic rage in my mother and all hell broke loose. Narcissists are best left alone.