Well, it sounds like an "emotional affair" is one thing that they are doing. Also, abuse is a deal-breaker. But back to your question ...

From my own experience, I don't open up because if I do my feelings will be invalidated. As in I end up having to apologize for my feelings rather than having the other party respond with something like, "I'm sorry you feel that way. What can we do to address those feelings?" So maybe you could look at how you react when someone does try to open up and attempt to address the situation without invalidating or judging to other person?