I feel extremely blessed my in laws are part of my life. W has basically abandoned them. W blames me for telling them she was on drugs, which is untrue. They saw her try and make OM part of their life months before we even talked about divorce. They had met him on several occasions (while still married) and they do not like him at all. After separation, she claimed I was keeping money from her, then turns around and shows them about $10k in new furniture she bought. Then she gave them an ultimatum: they accept she, OM and kids as a package deal or would not get to see the kids. The final straw was my daughter's birthday party. Her parents mingled with everyone. W came late, walked past her brothers family without saying a word. Later, she left for 30 minutes and returned. At the end, she stole a gift so she could keep it at her house. She and her parents had a catastrophic blowout later that day and have not spoken in months.
To add fuel to the fire, W cousin has injected her opinion that family should back my W and not me. It has turned a big portion of the extended family against my in laws. I'm sure "facts" are based on W's lies.
I don't know if this situation will ever be repaired.