It's easy to forget in our culture of celebrity gossip and social media overshares that most married people live very private lives. Marriage, even bad marriage, is an intimate thing very often crafted of secret histories and shared truths. And it is impossible to know exactly what goes on behind other people's closed doors.

Just think about some celebrity splits that came as total shockers: Al and Tipper Gore. Elizabeth and John Edwards. Remember Anthony Weiner and Huma Abedin and further back Governor Eliot Sptizer and his then wife Silda. Even the most-trailed celebrity couples can hide the truth. For a long time, Khloe Kardashian kept up appearances as then-husband Lamar Odom reportedly disappeared on days-long crack binges.

A recent example can be seen in the can't-turn-away car wreck case of Justin Ross Harris, the Georgia father charged with murder and second-degree child cruelty after leaving his toddler son in a hot car for seven hours. The public has been fixated on one aspect in particular: Harris's ripped-from-the-tabloids personal life. Details have emerged that while 22-month-old Cooper sat trapped in the car, dying of hyperthermia, Harris sent explicit texts to six different women (none of whom was his wife), including one underage girl who was also the lucky recipient of a photograph of Harris's erect penis.

Six women! It's one thing to leave your baby in a hot car, the outrage seems to go, but to leave your baby in the car while you are off cheating on your wife and sending lewd photos to young girls? How dare he!

But let's be clear: It's no worse to kill your baby while you commit adultery than to kill your baby period. Here is a man who allegedly researched such topics as how hot a car needs to be to kill a child and how to survive in prison, but whose excuse has been that he "forgot" Cooper was in the car. Here is a man who drove for some distance -- Cooper, dead, in the backseat, his body already in rigor mortis and the stench by all accounts overwhelming -- before pulling over to check on the child, but not bothering to call 911. At the end of the day, does it matter how many girls this guy texted while his son perished in the parking lot outside?

Consider the reaction to these revelations and it would seem that, to many, it does. There's been much speculation -- especially as Harris's wife, Leanna, comes under suspicion for her own role in Cooper's death -- of the state of the couple's marriage. It's been revealed they were in financial trouble; they had taken out $27,000 in life insurance on Cooper not long before. Leanna told police that she knew Justin was cheating on her. The question has been raised: Is that what made them do it? The stress of finances, the stress of fidelity, the stress of, well, marriage? Harris's defense argues that what happened was a terrible accident -- a parents' worst nightmare that killed 44 children last year alone. The couple has told police their own paranoia about leaving Cooper in a hot car is what prompted them to research children dying in cars -- an eerie coincidence if it is to be believed.

But less than the way Cooper died, the reason for the rabid fascination surrounding this case seems to be the fear that the Harrises could very easily be people you know, and the worry that perhaps we don't know our friends as well as we think we do. To the many friends and shocked neighbors who have piped in to say that the Harrises were a regular couple who loved to brag about Cooper, the pair seemed pretty "normal." A pastor at the couple's church described Justin as "a typical, loving father of a toddler."

And yet it should be no more shocking that the Harrises could have hidden this potential for murder from their friends than it is that they went through with it at all. We simply don't know the real truth behind other people's lives -- or worries, or desires, or fears. As the case moves forward, we'll undoubtedly learn more about the intricacies of the Harrises' union. But it's just gossip. In thinking that the scraps we might be getting about the problems in their marriage will offer some meaningful clues as to what he or they were capable of, we're forgetting that the only witnesses to a marriage are the two people in it.

Part of living the new American dream, for many, means projecting a certain image. Marriage is no different, maybe especially for those who have a real reason to project an image far prettier than the reality it shrouds. Consider Leanna's eulogy at Cooper's funeral, in which she characterized her philandering husband as "a wonderful father." As former prosecutor Philip Holloway told the Today show on Monday, "This was not an ordinary marriage, and there is probably a lot more going on that we just don't know about."

But, then, isn't there always?