I think what happens when things like a dirty glass by the sink get used as the reason for a relationship failing is a little more subtle and drawn out. Seeing the glass by the sink probably triggers some repetitive negative thought about the partner (wtf, why can't they just put the stupid glass in the dishwasher??), which leads to a gradual shift of one's attitude towards that person in general. That slowly snowballs as the slightly more negative attitude comes through in more interactions and you start getting frustrated by more and more little things your partner does, which triggers more repetitive negative thoughts, until you find that you can't stand the person you used to love. The final reason for the relationship failing wasn't the dirty glass, but it may have been the primary catalyst.