When my WW got involved with OM she was living with me and the kids. Gradually she spent less and less time with them. She used to cook meals and this slowly stopped to the point where she barely made anything. She even told me "Our kids are not neglected because I don't cook. I provide for them financially and emotionally."
Several weeks after she started seeing OM my eldest daughter was having abandonment issues. WW acknowledged this and said "so imagine when I'm not there."
He behavior changed completely. She spent less and less time with them. She would come home at midnight like a rebellious teenager. She lied to the kids and told them she was seeing friends.
We were supposed to have 50/50 custody but because OM lived several miles away and she had to work at the office she couldn't take them to school or pick them up afterwards so she asked me if I could have them during the week which I happily agreed to.
What happened is she moved to a neighboring state and ended up only getting long weekends with the kids. My oldest daughter didn't want to stay for an entire weekend so she'd go for one day a week. Sometimes her mother would pick her up and drop her off the same day.
She insists that she left me and not the kids but nothing could be further from the truth. She abandoned her family and now takes care of another man's kids.