Bah Steve, the time has come to cut her loose. You have a boat load of content to keep you going for a very very long time. Something tells me that you could make more with her gone then with her around sucking the life out of you and your staff.
People, she was a paid model, she had a job! She didn't do a hell of a lot for what she got. She has been educating herself for years (with income she earned from LS) and is even on her way to owning a home and she's only 22. It's not like she was performing heart surgery. She was paid over a course of 4 years, if she wasn't making bankm it would not have taken her four years to figure it out. If it wasn't for her popularity at the time and Steves internet savvy and marketing skills, she'd be doing what most 18 year girls (by most I mean girls in the sex world bizz) were doing to get through school...that's right, stripping at some dumpy bar and would have shit loads of students loans to pay off.
If she is disruptive to the other girls etc., it's not worth the headache, sure she was number one and 'was' being the core word here...let her go..hardly seems worth the trouble! If someone else wants to take on that problem let them, you have what you need and like you said, "she'll be 18 forever in Lightspeed Land"
