We have been having a lot of fights lately but still love each other and are best friends. He can see me there. No wonder your boyfriend is starting to get scared.
Death is dreams is a consistent metaphor for change, growth, and separation.
In your case, because you two have been fighting recently, your boyfriend may worry that he's in danger of losing you, and he may feel helpless to stop it. Another interpretation of your dream would be that your boyfriend's death really indicates change and growth in himself, that he is having a hard time communicating or expressing to you. You and your boyfriend are lovers, but you also are best friends. In a world where change is constant, good friends need to give each other freedom to grow. In no way are these sites intended to substitute for the professional services of a medical doctor.