Obviously NC but mumsnet can see I’ve been around for a while.
My dad, in his late 60s instead of retiring took up with someone in her early 30s. My mum was heartbroken.
• At one point my mum went to the house my dad bought for OW to try and reason with her (bad idea, I know). My mum was in her 60s and this woman started beating her up. OWs sister was there and is a witness: My mum is very religious and all the time she was being attacked she did the ‘turn the other cheek’ thing and was singing church hymns. Her jaw was fractured and she lost a tooth.
At this point mum bought her own place but they did not legally divorce for reasons.
• About a year after this my dad and the other woman had a child together. They named him after my grandad. My dad took things from mums home to where he was now living with ow (bbq, party punch bowls etc.) for a ‘baby welcome party’. I think this child caused my mums mind to go. She went to OWs house and lit papers in the recycling bin on fire. The fire didn’t take at all. My dad reported DM to the police (he did not do anything after my mum was attacked. DM did not want to report it too). They took a statement but nothing happened.
• They had a second child. My mother got an annulment (she and my dad have four children 
).
• OW and dad had a big wedding. Some relations went but some did not go in protest. Siblings and I did not go.
The oldest ‘half-sibling’ is now 5. In all that time I’ve never met OW in person or the children. I see my dad occasionally and we never mention any of it.
I know the violence sounds awful but we are not a ‘rough’ family. My mum is all Charities and Church.
How do we move forward? Can we?
He’s getting on in years and I don’t want regrets.