I was reading your posts and saw a few common acts from various W that I believe you need to watchout.
The "I am going to sleep in the basement" comment is in fact "you should go and sleep in the basement". The "I need space and will go to my parents" is in fact "I need space and YOU should leave".
I presume that you are the breadwinner at home and if she has held back or changed her mind I found it means she has realized that if she leaves the marital home she will lose a lot of her perks of being your wife and she is not at that stage.
When a spouse changes passcodes without informing (i need to for work security but inform my wife and son) on a pc and especially on a smartphone with whatsapp and sms it is a big red flag. If you notice she is keeping her phone tight close to her even to go to the bathroom for a cr@p then the chances are she is in the middle of an EA. I am not saying that it is 100% but the signs are there.
I also see that when women work out and start attacking the husband, talk about moving the sleeping or living arrangements and belittle the husband they are losing respect for him which means they are beginning to let another one in.
I also found that when women complain about the housework and such it is when they are in an EA and are more interested in the fantasy world offered by the EA than the real and mundane one offered by the husband.
I think your MC sessions will get you nowhere until you get to the root of her attitude and i would voluntarily cancel anymore MC sessions and tell her you see no point in continuing and need to do your own evaluation on your MR and see what will be the next step but you are not ready to continue walking on eggshells at home.
I would also add that it was a nice family home, right now it is a house and you are questioning if it is worthwhile continuing like that and breaking the sanctuary of the clam that it once was.
I would also suggest YOU mention to her that it may be a good idea if she stays at her parents for a while so you can get your space to think things out, concentrate on your exams and see what the next steps will be.
I know many will find this wrong or confusing and it is my opinion and suggestion but you do need to change the dynamics. Start thinking on what you need and stop being so dependant on her whims.
You need to start controlling your emotions and life and not subject your happiness to her tantrums. Kids throw tantrums.
I may get bitch slapped by some members but it is my opinion.
