Patri, what is your fixation with blame? Either the individuals accept responsibility for their individual actions which have damaged the relationship and work to fix it and stay together, or they accept responsibility for their actions and, having tried unsuccessfully to fix the marriage, take what they learned about themselves and apply the lesson to their next relationship, or they refuse to take responsibility for themselves at all.
Are you rather concerned with the Yentas (both those in pants and those in skirts) trying to figure out who was “to blame” ex post facto? Frankly, it is no one’s business except perhaps someone contemplating marrying one or the other ex-spouse. Does every married person’s shtick and baggage get discussed, analyzed and condemned too, or is it only those who are divorced who are “blessed” with the “concerns” and the “observations”?
Communication. Trust. Partnership. Respect. Emotional Support. These are some things that are the foundations of a successful marriage. If they begin to weaken, the partners in the marriage need to take responsibility for strengthening them. If they disappear, the foundation of the marriage is unstable, and it will be washed away by the next storm, be it emotional, financial, child-related, bereavement, or something else.
Remember one more thing, though. A broken marriage is a terrible thing. It sucks the strength, confidence, money, faith, and energy out of both involved just when they – and their kids, if they have them – need these most. But a miserable marriage where both have tried and failed to fix things, or, worse, not tried at all, is simply like swimming in a pool of poison. at that point it is better for everyone involved to move on. And “blame” is the least important consideration.