Empathy is the most fundamental building block of any relationship.
The concept is that if you are able to think about your partner and what they are thinking and feeling, it may make you feel more connected to him or her. It may take some practice. It requires a bit of focus to think about things from his/her perspective. It also does not mean that you should negate your own feelings. It is about understanding yourself and your partner better. If you feel more compassion for your partner and he does for you, you may feel more sexual. There is generally a myriad of things affecting one’s desire, however with increased empathy you and your partner may be better able to problem solve together. This is of course not always the case, frequently when your desire dips and you are feeling pressured to have sex, it may be very difficult to imagine the whole experience from your partners point of view. This web of feelings is complicated, however with time and practice, empathy is certainly something you can get better at it.
This does not only apply to sex, it applies to relationships in general. When we are in the midst of our lives, it is sometimes difficult to access empathy for our partner. You may feel alone in coping with your life. However, it will probably benefit you to share your struggles so that your partner can have more empathy and understanding for you. I find increasing your empathy can go a long way towards building understanding and connection between you and your partner.
This idea is discussed at length in the book Hold Me Tight, by Sue Johnson. She discusses how to improve your communication and connection by building empathy. She suggests having a series of guided conversations. She believes that by exploring the patterns of connection that you and your partner have established, you can gain insight and resolve some of the difficulties that may be troubling you.