Yes, I think you have unfinished business with your deceased ex-husband of some kind. Could be related to buried feelings you have about a conversation, or situation between you two in regards to your marriage or your son. I don't believe in ghosts or an afterlife and don't know what your religious or spiritual belief system is. If you are religious and spiritual, it could be a visit from your deceased ex-husband. If you are like me and are a non-believer, and tend to fall more on the science/psychological explanations for dreams, it could definitely be that you are still grieving the loss of your ex-husband in your own way. Grief takes on all sorts of forms for people and definitely displays itself in our dream state. Dreams are more than our brain self-cleaning every night. Our subconscious works out stuff while we sleep, that our conscious mind hasn't yet.

When I lost my dad and my best friend, part of my grieving process was to work out "stuff" with them in my dreams. I also talk to them aloud all the time, and this helps me process the loss still, years later. Keep a dream diary. Write down as much detail as you can remember b/c I guarantee you will see the same symbols used again and again. Symbols that your brain chose for your conscious mind to process, b/c it's your brain after all. I love discussing dreams. They often have layers upon layers of meaning.