I know you care very deeply. I know you truly want to reach his, and to keep everyone safe.
But you staying is NOT going to accomplish that. This child is so far beyond what can be helped in the home that it is scary. Truly frightening.
IF you can get this child into some sort of lock-down facility for a couple of YEARS then you MIGHT have a TINY chance at "fixing" him so that he can have a decent adult life as a functioning member of society.
If this child makes ONE report of abuse, especially sexual abuse, by you then you can kiss your life goodbye. I actually know a man who was accused of this by a student at the school he taught in. By the time 4 weeks after the accusation that the girl admitted she made a fake report it was TOO LATE.
His entire career was destroyed. His wife lost a lot of HER business because the community heard that he was accused of molestation. Their children were tortured in school - many lifelong friends were no longer allowed to play with their kids, nor were many of these kids supposed to even TALK to his kids at school.
There is NO FORGIVENESS once the accusation is made for this kind of thing. You are delusional if you think there is.
IF you are cleared of all charges (NOT the same thing as having charges dropped by a LONG shot) then people will forever and always believe it was because no one believed the child, or that there just wasn't enough proof. It will NEVER EVER EVER be back the way it was.
You know, when he is playing with that child half his age that he is abusing the child.
You know he has abused his own MOTHER sexually.
All of your love isn't going to mean one thing at all unless you get this child away from the community. He is a major danger to EVERYONE.
You have so much to lose by staying. There won't be a good outcome because there simply cannot be one. the child probably inherited some mental illness or whatever is driving this, in addition to being abused by his biofather and the atmosphere in the home until the divorce.
Take off the blinders. To fix this kind of problem it takes years and years to even get the child to the point where they CAN be helped.
By leaving you can make some comments to others that they need to keep their kids away from him because he abuses anything weaker, including the CAT. By staying to continue the cover-up of his actions.
I hope that you can see, at some point, that the only safe thing is to be FAR away from this child. Once he makes an allegation you won't be able to do anything to help anyone.
And at that point, when you say "but he did this" EVERYONE will ask you why you stayed, why you didn't tell the neighbors, teachers, experts, everyone what he was doing.
for that matter, why haven't you gone to the neighbor with the young child and warned his parents? Why haven't you gone to the school, the doctor, the therapists and shrinks?
I don't mean to attack. I do mean to let you see the most likely outcome. And to ask if you even know why you stay with-o alerting potential victime?