My brother and SIL had an ugly divorce. I don't know if he had an affair but SIL acted as though he did. She was very bitter and resentful. She hated him. Fair enough. I think he's a narcissistic A-Hole myself. I was never his biggest fan and I no longer have contact with him either. He went on to have another child, and kept it a secret from his sons. Imagine how betrayed they felt when they heard the truth years later. That was the finally nail in the coffin. SIL closed off our contact with them after that. We sent Xmas cards, but never got a reply. We'd hear from them occasionally, but the bond that was there when they were younger disappeared over time.
I don't miss my SIL. We were valuable based on what we could do for her. She said nasty things about my brother in front of the boys. She said nasty things about my brother in front of our mother. My young nephew asked her not do that and be more respectful around his grandmother. He was wise enough as a pre-teen to know that was not cool. My mother could recognize her son for the ass that he was, but she didn't need to hear that in front of her grandchildren. She couldn't do anything about it.
They are young adults now and don't have contact with their father. He was stupid enough to think, like many arrogant WS's do, that when they got older he would have a relationship with them that he didn't have when they were younger -- with no work and no effort. Life doesn't work that way. I told him he would regret his decisions one day.
It's sad that we all got painted with the same brush simply because we were related to him. We didn't fight to see them or push SIL because she was so angry and resentful. We all quietly went away. I regret that and I've lost touch with them.
Their parents went through an ugly break up and they were caught in the middle. Our whole family misses them. I worry about them. I wonder what they are like now or where they are. I don't even know why I'm writing this post except I miss my nephews. I feel like we all failed them.