I feel for you, your situation is very, very hard. Based on your description of events, your wife got to a place where she felt "trapped" -- either because you were controlling, or she felt helpless without you being controlling, etc. When people feel trapped, they get worse and worse until they have a crisis and make a change. This may explain your wife's behavior, it may not be mental illness, it may be a relationship problem. I was convinced that my W was depressed for years and possibly bipolar, but when we fixed the M and I started providing the emotional things she needed, the mental health issues were gone. Don't jump to that conclusion *yet*.
Anything you do right now to pursue your wife will make her fear "falling back into the trap" and once again feeling loss of control. That's why GAL Man's list of 35 rules to live by above is so important.
You may also want to read "Tough Love". It suggests that when your W pulls away, the ONLY appropriate response for you is to pull away in the opposite direction. That's the only way to get her to try to connect back. If she takes a step right, and you take a step right, she's going to take another step right, and eventually start running to get away. If she steps right and you step left, and then take another step left, she will stop stepping right, and may eventually step back to where she was. i.e. the more you pursue, the farther she will run, and the more ground you then need to reclaim. I wrote a long post on this in response to "am I getting flushed down the toilet" on this forum, see if you can find that -- his situation is very similar and the timing is about the same too.
Know that if your W is on a spending binge, you may find yourself responsible for half the marital debt if it comes to D, so you may want to see a lawyer both about your custody rights and your financial exposure.
The best thing you can do right now is GAL -- try using www.meetup.com to look for things in your area. When your W calls or comes by, the best thing you can do is to "have something going on" where you appear happy -- i.e. have friends there, be on your way out to do something fun, etc. You need to once again be an attractive person to be around, and that requires you to act as if you're having good times following you around. If she comes by and you're sitting at the kitchen table with your head in your hands, that's not going to be a very attractive scene to want to be part of. I know it's hard, but you have to FAKE IT for now. Eventually you'll just be doing it and not faking it.
Also, you should set some rules about when she can come over, and what she can do when she gets there. Set some boundaries, this helps to establish respect. You cannot control her, or set rules for her behavior, but you can establish that she can't just come by anytime she wants, she needs to call first -- that will allow you time to prepare so that you're in a good mental state and appear "fun". When she gets there, she can't rummage through your stuff, if she needs something she needs to ask for it, that kind of stuff. Establish that your life is your life, you will be friendly and helpful, but you also have boundaries.
Helpful?
Accuray
Married 18, Together 20, Now Divorced M: 48, W: 50, D: 18, S: 16, D: 12 Bomb Dropped (EA, D): 7/13/11 Start Reconcile: 8/15/11 Bomb Dropped (EA, D): 5/1/2014 (Divorced) In a New Relationship: 3/2015