When I was a stepmother, there were red flags shooting up all over the place that my stepchildren's custodial mother's live-in boyfriend was abusing the children.
The children admitted nothing. They were too scared that they would not be believed by anyone who could save them, and admissions would land them in big trouble. They were right about that.
The first flags were merely indicative, but I could not convince my now-former husband to see that these were flags. The flags increased in intensity, until I was positive.
Neither my former husband nor the children's mother would agree that there was a problem.
I divorced my former husband because of this, when he refused at the last minute to take custody of the children because he decided they wanted to live with us because they wanted to get back at their mother because they were mad at her.
Two years later, I went to visit him and the kids (I had moved far away). Immediately, they sat me down and told me the whole story, and it turned out I was 100% right.
Their father had refused to listen to my analysis at the time. He had a picture of his ex-wife, the children's mother, in his mind, and anything that didn't match with that was irrational because it couldn't happen in our family because she was a good mother. He made excuses for the all the red flags.
Their mother, IMO, was mostly interested in not rocking the boat financially because she had a better lifestyle with the live-in boyfriend than without him (more money to spend on herself). I do think she took the boyfriend's side over that of her kids because of money. I don't think she knew the extent of the abuse.
I divorced him because the lawyer we consulted about gaining custody said the situation was none of my business, that I was only the stepmother who had no legal rights, and there was nothing I could do about it when my husband changed his mind.
Anyway, the point is my stepchildren were being abused by their mother's live-in boyfriend. No one with power (their bioparents) would do anything about it. They were ages 9 to 12, and none of them said one word to anyone about it.
And about those red flags, I think most everyone here would agree that they were red flags. But in the course of ordinary life, there are plenty of people who would not pay much attention to them.