First let me say that as most relationships, I doubt either of them are without fault.
I'm not sure what you mean by "fault"; if he did abuse her, that would be his fault completely. Even if she provoked him, his response is his choice.
Now, it appears you are equating mistrust with abuse.
Consider the evidence.
Look at her past pattern. In a dispute, LE was called. I don't recall any of those calls to LE resulted in an abuse charge.
In Tennessee, the police are obligated to arrest if they actually witness abuse or enough "evidence" of it. Abuse often stops instantly when the police arrive, so police have no evidence by which to make an arrest. As we know, however, lack of evidence is not the same as no crime. We simply do not know what happened there, but if her pattern had been to call for help whenever any argument occurred, I can bet she would have called more than three times.
No abuse reported, her leaving to go to AL, her going back to Signal Mountian, her dropping the kids off at the house (presumably alone) and not calling LE indicates that she was not in fear of abuse.
We do not know what agreement the two had regarding when she was to return. Besides, if the particular conflict that prompted her to call had cooled down, she might not have perceived an immediate danger in returning. DV works in cycles like that.
Those things could indicate an unstable person.
If she was in fear for her life, I would expect her to secure the children in a safe place and not the items that she did. If she in fear for her life, I would expect her not to return the kids to Signal Mountain. If she was in fear for her life, I would expect her to call LE while in AL.
Her behaviour seems more bizare than his.
Her actions and a lack of finding the Jeep, points to a self disappearance.
Securing items indicates to me a definite fear as well as planning ahead on her part. I'm not sure what would have been accomplished by calling LE in Alabama, unless something more happened in Alabama. Unfortunately, being married and having children, she had quite a process ahead of her if she were going to divorce him. Staying in Alabama would have accomplished nothing toward that end.
Nothing of her actions indicates to me a planned disappearance. The more time that passes without finding her or the jeep, the more unlikely it seems that she disappeared on her own.
We have some very clear evidence that she was a devoted mother, and we have no evidence beside his word that she was mentally unstable. We also have the very objective evidence of a black eye on the weekend of 4/10.
I certainly don't fault anyone for having a different opinion, however. This is simply mine.