Maybe you need to work on building the romance in your marriage. If you feel good about that relationship, I guarantee empathy and compersion becomes easier.
You share more fiduciary type stuff with your husband. In a sense, he's probably always going to be more important. But surrendering "ownership" of a partner's body is a liberating experience. Does he give you attention and make you feel wanted, desired, and appreciated? What would help you feel that?
With D, I hate our time constraints. Things like watching him play video games while I read is relaxing for me - For me, unstructured time like that in a relationship is fundamental. I love sharing, but I really enjoy just screwing around. That's something that really makes me feel loved in a relationship. If he had more than one girlfriend or another partner, we'd have to rush through our activities. Are you feeling rushed with your husband, or like your time is too crunched?