My medical romance that is coming out in September has a prologue. When I turned it into my editor it didn’t, but I was asked to add one because of the reunion aspect of the hero and heroine’s romance. My other two do not have prologue. I have a historical that is on sub with my editor (fingers crossed) and it also has a prologue – again a reunion romance.
I think it is really dependent on the story, and you have to have it mean something. If it’s just a backstory dump then it can be dropped usually.