So what's the reason for divorce assuming that two people got married in the first place for "the right reasons" (read: both took the vows intending to make an honest go of marriage). When you've gotten married for the "wrong reasons" (got pregnant, to get out of parents' house or some other living situation, wanting to control the other person, etc.), the reason will be apparent. I've no idea how many marriages that would account for. Probably a lot but they aren't the ones I struggle with. Not even the ones where one or both admit to themselves when already in that it was a mistake but you "play it out". And not the ones that suffered the especially poignant trauma of losing a child where I imagine just the individual act of breathing is difficult enough to manage let alone navigating your role as part of a couple.
No, the reasons for divorce that I struggle with are the ones where the parties enter with a good faith "love conquers all" mindset and still end up in a heap because those aren't a small number either. The ones where as sentient human beings we've entered into it "reverently, discreetly, advisedly and soberly" because we know none of us are a perfect clean slate and we all have our own peccadilloes, micro traumas, macro traumas, etc. we bring to the marriage and agree to work through .... and then just don't. 'Cause those ones at least should all work, right?