Death symbolizes you need to eliminate negative influence from past. An aspect of you has to die before another aspect can find expression. For example, to dream of the death of your father means you need to eliminate negative influences resulting from your relationship with him.
To dream of your partner dying is indicative of being in a relationship you do not want to lose. While it seems dramatic, the dream is trying to get you to face your fear of losing your partner in order to get over it. This is a common dream when you find yourself in a relationship that feels like true love, particularly when it follows a bad relationship. The most common theme is your partner dying in a car crash.