Teenage Daughter Tearing My Marriage Apart...Please Help!?

I have tried and I have tried. At this point, I have no idea what to do. My daughter is 18 years old and walks all over her father and me. We have provided her with a wonderful home and support system, but she continues to take it for granted. She began skipping cl in the 9th grade, which got so bad that she left her public high school and began bouncing from one alternative school to the next. One semester away from graduating and she decides to drop out. I personally handed her a comfortable job in retail, courtesy of a good friend of mine who happened to be a store owner. A few weeks into her part time job, and she decided she didn't want to wake up for work any longer. Her father and I have offered to purchase her new furniture, clothing - anything - but this young adult would rather keep her bedroom in shambles (it looks like dumpster exploded in a jail cell) and recycle the same rugged pair of sweat pants and hooded sweatshirts, no matter what the occasion or temperature.