I dunno if this is the worst thing Dick's done, but in the pulp noir annual he seduces a woman and marries her as part of an investigation. I forget the details, I think she had been married to a mob guy who got killed.....I can't recall, but she had gone through a rough patch and Dick used that to work his way into her life. Stone cold.
He never sleeps with her, and I can't decide if that makes it worse or better. I mean, sleeping with her under false pretenses is pretty damn awful but think how wrecked that poor girl is; she went through the original trauma that put her in Dick's crosshairs, has legit feelings for him, and then endures the stress of wondering why her boyfriend/new husband isn't even interested enough in her to share a bed. She's just a ball of anxiety and depression by the end, and a lot of it was caused by Dick.