I'm not so sure she is covering up for hubby. Think about it...
It's coming down to the wire. She's probably past the point of desperation, and I think if she thought it would get her off the row, she'd have said something before now.
But then again, if she does involve Darin, she blows the whole "someone came into my house and killed my babies" argument right out of the water.
It's just so difficult, so inconceivable, for any normal person to believe/imagine a mother could do what she did to her own children. It's the sort of story you relate to someone and their immediate reaction is "No... how could a mother do something like that"
You just don't want to believe it, because it is just sooo horrific and unthinkable.
In that way, I've always kind of hoped that there was a third person involved.
However, if it comes out in the end that she has been proven guilty of murdering her two little boys, I think everyone here knows my feeling on the subject...
Strap her in and let the healing begin!