At age 19, SD is going to work, or not work, as she chooses. Her dad talking himself blue in the face will have no effect.

When I was young my parents left it up to me whether I attended college, or worked, or did both, or did neither. Around your SD's age, I was unstable and dropped in and out of school, got hired and fired, or quit - some good jobs, some crappy jobs. My parents had one simple policy toward me. I could live with them when I wanted to. I could help myself to what was in the refridgerator at their house. But that was it! They wouldn't give me a dime. By the time I was 26, I had completed a job training program, gotten a job and my own apartment. They never had to do a thing for me again for the rest of their lives. I've been pretty much on my own ever since then. That was over 35 years ago. They're both gone now.

Here's another thing I would offer. You're not doing yourself any favor by tracking the verbal and texted exchanges between your husband and SD. She's his daughter. And she has a mother of her own. What transpires between the three of them really needn't be your concern . . . . . . unless it costs money that belongs to you. Otherwise, you might want to try ignoring all what goes on between them. Your husband owes you a certain modicum of time and attention. Expect that, and channel it how you want your together time with your husband to go. Beyond that, let husband and SD work out their relationship however they will. You can't really influence it.