I understand her way of thinking as well but if it causes her to screw up then she is solely at fault. Rick gave her no reason to be suspicious of him at all. Rick had actual reason to believe Pete was a problem.
Pete would most likely not have killed Jessie. he only got murderous because he felt his life was being taken from him. He would have kept abusing her though so it is still good he stopped him though the way he handled it escalated things as well.
Yeah I do agree it would be her fault if she does let him out. I do understand her reasoning though, so I will cut her some slack but nonetheless she will be the one responsible for the death and destruction caused if Negan does break out.
I can see an argument between the two going too far and Jessie could have been seriously hurt. That's just how domestic violence works. It's kinda a shame though she broke free from that and died in a couple of days...