Jamie means well, and I believe in her heart, she believes this of Jonathan, or she did up until her last interview. I have no idea how she feels now- if anything has changed or if she still feels the same way towards him.
However, the Jonathan that she was with back when Lucas was born, and the man he is today, with Emily, are quite clearly two different individuals. Jonathan would probably never have turned his back on his family, had he and Jamie stayed together, because they didn't have an abusive type of relationship, and she didn't abuse Lucas or any other children. Emily, on the other hand- well, we all know about her.
Jonathan quite clearly changed after he paired up with Emily. He is not the same man now. He chose Emily's side over his family, over Jamie, and worse of all, over his abused son! He's also abusive himself. Did it ever occur to anyone that some people are actually turned on by violence? I don't know if that is the case with him, but why would you stay with someone who is allegedly abusing you and the kids, especially if you haven't been abusive or abused before? There is just something so sick about him defending her and denying she abused Lucas. I just don't see it in his personality to take much crap from anyone, never mind Emily or any other woman.
I probably am alone in this thinking, and that's ok. I could be very wrong, but looking into his face during that first interview, to which he displayed anger about the abuse allegations. He displayed anger again in another interview, saying people were wrongly accusing Emily of hurting Lucas online (in FB groups, etc). He was angry! He was angry at everyone else, but the one person who he chose to have this abusive relationship with- Emily. He chose to stay, as did she.
Just my opinion and thoughts. I have no facts to back this up. Just my own observations.