SaltyDog, welcome to the site. Sorry you are going through this but there are many good posters here that can help.
Obviously when you start introducing health issues that affect things, as well as meds (hers not being right, and you being on ADs) then that is another variable that can cause issues. I am glad to see you are in IC and on different meds, but I am hoping that you will eventually be off of all ADs with therapy. (I have a personal belief that too many people are immediately put on meds instead of going to IC to deal with their depression.) I think that is a great step.
Salty, your sitch reminds me a bit of mine. Without the studio and nesting. I am not a big fan of nesting. I think it confuses the kids, it becomes a new normal, and then there is the whole issue that the WAS is the one wanting to leave, why would the LBS leave even for 50% of the time? I advise LBSs that are considering agreeing to this NOT to.
You probably agreed to it out of trying to nice her back. In fact, that is a theme that seems to be running throughout your post. Playing family. Thinking things are getting better because you sleep together, have sex, being more vulnerable with her. All of that is in the category of "nicing" her back. You cannot nice her back. And you've learned this the hard way with the dating site thing.
Here is the thing, I had a very good advisor early in my sitch give me this simple truth. WAWs do not need their own place to find themselves or work on the marriage. They need their own place to sleep with other people. Despite all of the family stuff and normal times, the elephant in the room is that she still goes to the studio, and expects you to when it is your turn. That is NOT normal. So no matter if the normal times are 50% of the time. or 75%, or even 90%. The time she is at the studio or expects you to be is the more important signal here.
But the reason you are confused is because you are dealing with an emotional creature that, right now, doesn't know what she wants. This was another big learning in my sitch. From minute to minute my WAW didn't know what she wanted. One minute she wanted to stay, the next to go. Your WAW is likely dealing with the similar feelings.
So what can you do? Obviously you need to detach. Getting out of the obsessive "checking up on her" will be a huge benefit to you. If you are that way when she is away, I doubt if you aren't that way when she is around. And she feels that pressure and pursuit from you. It is probably palpable. So detaching, backing off, giving her time and space is the best first step. Remember, the goal here is to remove ALL pressure and pursuit.
Second I would end the nesting. "I have thought about it and this isn't working. I think we should update the studio to a full apartment, and you should move there 100%. I will stay at the house. And we will work up a custody schedule." I have never seen nesting work. And if you do end up D'd you won't be nesting anymore. So I would rip that bandaid off.
Third, stop letting her cake eat. She is involved in an EA (I doubt it is over). She is advertising herself on dating sites (I think your reaction to her telling you this made her later say she was off of them.) She is wanting her own time and space at the studio, but then having you as her consolation prize (calling at midnight) and coming over to play family when she wants to. Ending the nesting will likely help with this, but you really need to study what it means when a WAW cake eats. If you haven't read DB/DR, get DR and read it.
Fourth, start going out and GAL. GAL is so important. It is much less likely to obsess over what she is doing when you are out GAL. GAL shows you that your life is going to be just fine no matter what she decides. GAL well helps you with the detachment process. There are no negatives to going out and GAL!
And then keep working on you. IC. Working on 180s. Becoming the best Saltydog that you can possibly be. That will set you up well for what comes next, whether she decides to stay or go!
Salty, the above is not easy. I understand that. It is easier to type it than to actually act on it. But this is what I think you need to do to start moving forward, start moving on, and to start living YOUR life again, not living a life being her plan B hoping she picks you.
Keep posting!
M(53), W(54),D(19) M-23, T-25 Bomb Drop - Dec.23, 2017 Ring and Piecing since March 2018