Dream fear

So today I had a doctors appointment came home to go news that I will be seeing my baby soon. After I made breakfast for my fiancé and I, we went back to take a nap before he went to work. After he left I kept sleeping and I usually can remember all my dreams. But I hate to have some especially when im pregnant they been about the same. I dreamt that i just had my baby & we were celebrating at my mom house. I went looking for my fiancé and found him having sex with my older sister. I was heartbroken! (In real life I've asked him to have sex with me to speed up the baby process but he kept refusing) so to see him in my dream having sex was just ugh. Then he tells me he doesn't want to be with me anymore he wants me sister. ( in high school I had a boyfriend who was cheating on me with her) so it has always bothered me to see my boyfriends around my sister. Anyways at the end I asked him if he coming home and he said no! I argued with my sister in the dream and storm our crying (with family in my dream looking shocked) I end up telling my lil sister in my dream about it and then woke up crying.