Perspective can be deceiving. A lot of the difference in sex content between DMD and Melody comes from the fact the former's story development (especially about the main couple's romance) has progressed much less than the latter's one. IIRC, by the time DMD's story had progressed to the equivalent of where Melody stands now, F had gotten much less opportunity for sex of any kind from other characters (much less D) than Melody's musician MC got so far from Becky, Izzy, and Amy.
Moreover, Melody the character seems to have many less stumbling blocks than D about romantic/sexual exploration, and be much closer to the normal levels of horniness and sexual activity for a 21st century young adult girl. Melody's issues seem to be mostly about trust and responsibility due to her mother's early death and an absent/inadequate stepfather rather than D's extreme shyness and lack of confidence and lack of social experience adequate for her age due to having forcibly sheltered and manipulated by a controlling and emotionally abusive mother that sees her as a pawn in her get-rich schemes. So we can likely expect Melody to progress faster than D in her path, once the main couple acknowledges they are in a romance.