Just to add to what job said...my W did much of the same. She was convinced that I was checking her e-mail, following her gps on her phone, etc. Why? I really don't know. Why she even would have cared I don't understand either. She was living at home still then but had made it clear she wanted to go. She was doing whatever she wanted, whenever she wanted so what difference would any of that make?
Job is also right that, to this day (this was months ago), I wonder what exactly she was hiding. I'm sure she was hiding something I just don't know what or why.
I will tell you this...I wish I had done things differently now that she has left. I wish I had gone to a lawyer and at least talked long before I did. I ended up having to scramble to get my own lawyer AFTER she filed (and after she had told me she wasn't going to a lawyer, wasn't going to file, would use a mediator if it got to that, etc.). My W swore that she wasn't going to do so many things that she ended up doing. If I were you I'd start putting some money aside as well. My W left me with a negative account balance when she left with zero thought as to how I was going to live. As much as you hope and pray. As hard as you have tried to do the right things, use the DB method, odds are that things won't get better before your H leaves. I didn't do so many things I wish now I had because I HOPED that my M could be saved. Don't not do things to protect yourself because of that same hope.