I'm not sure which way I'm leaning right now. Taken individually I think her explanations are believable but the more they stack on top of one another the more improbable it becomes, and the more likely that she is lying about SOMETHING at least. I'm just not sure what that is, if anything. I don't think she was directly involved in the murder - Nathan is too vehement on that point and I believe him. I think weirdly he has a sense of justice (even if it is twisted).
But I DO wonder whether she found out, late in the day, after he had disposed of Becky perhaps? And he BEGGED her not to go to the police? But then again I can't imagine why any normal person would want to stay with someone after finding that out, father of your children or not. It also would've been the perfect reason for her to finally be free of him. My thoughts on this case are honestly all over the place (as you can see) and I still don't know whether I think she was involved to an extent - which would explain holes in her story, or not at all, as she claims. I however do not think that she was complicit in the murder or kidnap. I also believe her when she says that NM was controlling and violent. I do not think fundamentally that she is capable of taking the life of a young girl.
what have you seen that gives you this impression?