^^^THIS is how marriages fall apart. Resentment builds on both sides, and both feel like the other doesn't understand their side. Often the only difference between a WAS and LBS is who dropped the bomb first. Almost always, both have been thinking about it for a long time. But once one drops the bomb, it triggers regret in the other and then they end up here telling their story.
Wow that really hits home to me, because I do think back on how when my wife would tell me things that she felt were going wrong I would just immediately think she was wrong and become defensive, and the resentment would just build over time.