He doesn't fit the profile. He's too young and I think he would be carrying some SIGNIFICANT guilt if he did snap and killer her in a range over alleged affair. He has been scrutinized by LE and the media and amateurs alike, and no one could come up with anything suggesting a violent past or other behavioral indicators that he would be capable of something like this. Law-abiding men with no history of abusive or aggressive behavior don't just snap and kill their wives. True, maybe there could be a history of this and JC is not at all what he seems, but I find it unlikely. No evidence that he was in any way controlling or aggressive with Erin. If his whereabouts were unknown the day she disappeared, something would have come out about this. If his story didn't make sense, there is no way Erin's family would be as supportive. I understand that family inherently wants to trust the husband, but if there was something that didn't add up at least one would have spoken up by now. Nothing. Typically, if a wife disappears and the husband is a POI, something surfaces. Either accounts of prior abuse, controlling behavior, etc. (Drew Peterson) or an affair on the husband's part (Scott Peterson). There is absolutely nothing here. Though Erin is described as a quiet and private person, I think she would have confided in someone if she were at all afraid of her husband. According to some media accounts (I believe), there WAS knowledge about a possible affair.
In these cases, there is always a huge focus on the spouse or SO, and I understand that is warranted given the statistics. But given this focus, if you still have nothing and other very likely scenarios, I think it's likely that JC is completely innocent.