Why do I dream about people in my ex-boyfriend's life

For the last past days, i've been dreaming about people linked to my ex-boyfriend. I never dream about him and I, I always dream about a girl he's involved with being with him in front of me. Last night I had a dream that I was friends with his girlfriend's sister. What does this mean?

Dreams are random thoughts from people and things in your memory. They have nothing to do with anything going on now or in the future. The dreams simply mean that you have memories of those people.