Right when I read the subject title, I knew that you should probably pick with leaving her. After actually reading it, I can say that leaving her is probably the best option for the both of you. It's sad that you felt the need to let things go in your life to keep her happy, maybe that was a choice you wanted to make but I hope you aren't holding that against her.
She has some issues as you said and as long as you guys continue to date, she is still going to have those issues because she has you as that crutch to support her. A split would definately be good because you would be able to focus more on what makes you happy and it would give her time to get her life together. It's not an easy decision, but it's one you have been thinking about for a while now and the situation hasn't improved when you wanted to work on things (I'm guessing you have tried that route already).
You will want to split as soon as possible because the longer you hold out, the more you will be hurt and the more resentment you are going to have. The problem with that is how to go about it. There is a very fine line between being an insensitive asshole and doing it right and every girl and situation is different. I wouldn't say I'm an expert by any means but the bottom line of what to tell her is that you guys are clearly not happy with each other and need this time apart to find yourselves again (i.e. you do the things you like and she gets to work on her issues). Also, letting her know that moving in and what not is a big step and it isn't something you could see you two doing right now anyway because with how it is, it would be a disaster. You both have made mistakes, you both have faults and if you guys aren't enjoying each other's company, what is the point of being together?
I'm guessing no matter how long it's been going bad, she will still probably be caught completely off guard and it will send her on a hard downward spiral of hating you, hating herself and everything. As long as you can do this without raising your voice and taking cheap shots, it will be alright. The problem is that she might feel panic and try to talk her way back into it or try to contact you after the break up. Maybe she will ask you if you still care about her, make you feel guilty, pity. etc. Kindly remind her that things are not working out currently and you both need this space apart and hopefully she will get the message. No contact rule sucks but it's what needs to be done.
Go back out and do the things you like. Date a couple people if you feel like it. But some serious space is going to be needed and I'm not talking a week or two. I'm thinking more along the lines of three - six months minimum. Don't tell her that there is a time limit though. And that's three to six if she is self aware of what's going on with her and she is making a conscious effort to help fix what's going on in her life and make changes to better herself. Too often, and it's much easier for girls, to find somebody else to cushion the blow and be satisfied with how they are currently when they clearly have alot of work to do.
Like I said, it's not going to be easy seeing as how you could lose her in the process. But you now it's necessary and whether it works out with her or somebody else, you don't need her to be happy. You want her because she makes you more happy, and right now that isn't the case.
Waking up next to a beautiful girl,
Step outside and say hello to my beautiful world.