Well, of course we don't know all of your situation. But I would say that if she is living with her boyfriend, then she has a roof over her head and food to eat. And at 19, she's old enough to get a job. And she needs to do that.
She did something really awful, stealing from you. You should NEVER let that happen again. Did you change your card numbers? Passwords? You MUST do this. She cannot go through life taking from others. 19 year olds who steal from their parents shouldn't be given handouts. Regardless of whether or not she is trying to manipulate you, you shouldn't do it.
Forget about clearing the air. Leave her alone for a while. It shouldn't be all on her terms, mom. You DO know that you were raising her to grow up and be on her OWN, right? Just because it happened earlier than you expected doesn't mean that it wasn't going to happen. But it shouldn't have happened with her STEALING from you...
Let her find out what it means to work. If she ends up wanting to come home, tell her that she can come home, but she has to make things right with you first. That means paying back the money she stole and agreeing to house rules. And house rules include specific things, including WORKING.
You could tell her that you expect her to pay rent, and if you are happy with her choices later (and you don't tell her this, mind you), when she moves out again on good terms, you can give her the rent money back to help her with her new place. Or if she decides to go back to school, tell her that she must pay her own tuition and she can live at home rent free, STILL under house rules of some sort. She may not have a curfew being a college student, but she should have to clean and do chores.
As of now, none of this is on the table. But if you don't leave her alone and if you don't stop wringing your hands, she will never "miss" you. And she won't really grow up if you don't let her.