DMD is now more than ever living a double identity. The D only route and the D extra-fun route are becoming two paths that diverge in a wood.
If you want to keep D as a somewhat innocent princess then you may have to play the D only route.
By design the D corrupt route is going to evolve with D gradually changing her personality and how she regards sex in general. D is going to view sex in much the same light as her father and mother, sex can be for fun without emotional baggage.
I did find it interesting that Elena suggested a D+MC+E threeway that came to pass with Margo but the MC expressed doubt that D would go for it to Elena before hand.
Totally off subject but with as obsessed as Elena is with D's bodacious boobies and her father being a doctor who uses things to become closer to Elena it would not have been out of story canon for Elena to have showed up at Seaside with breast implants. Could still happen. Maybe her dad knows a good booby doctor at Seaside and sent Elena for a boob job. Beaches and hot weather seem to entice more elective surgery. After all look at how many more plastic surgeons (per population) there are in CA than in Vermont.