A recent study by researchers at the University of Padua and the Max Planck Institute for Demographic Research (MPIDR) has revealed that political differences between partners can significantly increase the risk of separation. Using long-term data from UK couples, the researchers found that those with different party preferences were substantially more likely to separate than those with the same political beliefs. The risk is particularly high when there are differences of opinion on Brexit.
A lot of people saying how does this happen, it happens over time with small shifts. It happens because our stability as communities and nations is changing faster and more frequently.
Question is when do you take off the wedding ring? (or mental equivalent) because your promise to this person is most likely the strongest conviction most people hold. For better or for worse, implies we understand a partnership has ups and downs that we ride through. A fundamental change is attitude could be seen as an up or a down.
Your assessment makes sense, but some of the mismatched relationships mentioned here sound like they started out unbalanced, and that must be the case. Some couples are clearly doomed much earlier on.