She loves him, but isn't in love with him. Just like she loves Elena, Jennifer/Georgina, and Olivia. Also, depending on what you chose re pregnancy, she is on the pill. Martin directly asked her if she is on the pill or not.Well anyone who has a basic understanding of swinging knows that there are no feelings involved. In this case D literally said she loves Martin and like someone said before, she lets him cum inside knowing she's not on the pill so from my basic understanding this is way more than basic swinging.