MissAdventure
Affairs aside, the children's welfare is the concern, regardless of whether the OP dislikes or blames her ex daughter in law.
The marital issues are neither here nor there, in the grand scheme of things.
I think you mean the children’s welfare should be the most important thing here, but sadly OP called this post “Daughter in Law Selfishness” and hasn’t raised any tangible evidence of concerns about her GC, just constant criticisms of DiL and constant praise of DS, it was the OP who brought the extra marital affair into the equation.
All I assume is DS is constantly updating OP and complaining about his ex (or how else would she know so much about DiL’s movements?)
I absolutely think both OP and her DS are right to be concerned, but instead of constantly updating OP about his ex’s personal life maybe DS should address his concerns. He sees the children so much that it shouldn’t be too hard to spot any changes in behaviour, signs of neglect etc and if he’s really that concerned he should take legal advice, speak the children’s school and speak to Social Services.
This constant criticism of DiL from OP doesn’t help her DGC if they are in “danger”