Most simply stated, empathy is the ability to put oneself in another's shoes - and also the willingness to respond to the person's needs. I believe it's one of the most important components of a happy, healthy relationship. Lack of empathy is a very common problem with couples. Many people never learned how to be empathetic from their primary caregivers or weren't modeled empathy by other important people in their lives. The good news is - it can be taught.
Here are 5 steps to practicing empathic communication when discussing a difficult subject:
1) Listen without interruption as your partner describes his/her feelings about the subject.
2) Pause and imagine how your partner might be feeling.
3) Reflect back what the partner has said in regards to their feelings such as, "It sounds like you're saying your upset because..."
4) Validate their feelings such as, "I understand that you're upset..." You don't have to get why - just allow them to have their feelings.
5) Offer support by saying something like, "Let's try to figure this out together."
This type of dialogue takes practice but the long term payoff of empathic communication is well worth it - and a key component of a strong relationship foundation.