My ex was coercively controlling to me and dismissive of /manipulative towards our child.
I left 5 years ago.
Last year, he assaulted my child. SS and the police didn't care and believed his claim that it was a lie perpetrated by me - at least, they believed it enough to close the case and tell me that the main issue was that I needed to encourage the father / child relationship.
In recent months, the father has been less toxic and seems to be treating our child better. He is possibly even slightly less nasty to me, though only just.
AIBU not to trust this?
YABU - people change and maybe he's better now
YANBU - this is all a facade and you are right to be afraid