Ah yes. Snooping. Both a blessing and a curse. It does a few things "for" us. It provides us with proof we feel we might need for lawyers or to remove the veil of lies that our spouses weave around themselves. In my case like yours the lawyer thing never really happened. Removing the veil revealed the alien monster that had been inside my W all along. The "bomb" of that though did fire off the starting gun for the real journey that I have been on. My W and I talked about snooping. She told me that she didn't blame me and that if the roles were reversed that she would have done the exact same thing. We are both human I suppose.
Snooping also allows us to feel connected to our spouses. These people who are so very important to us have embarked on their own journey. Having them be part of our lives for so very long we feel a desire to watch over them in at least part in the hope that their course will intersect with our own. We also feel an obligation to be there to rescue someone who has chosen to not be rescued. Each shift or wobble releases emotions within ourselves and probably the related brain chemistry. I feel that you are correct in making a comparison to an addiction. For many of us, we have a "need" to look even if we know that it will cause us pain especially as we over-analyze and mind-read based on the limited information that we get.
The other side of this as people including myself will advise others is that it is difficult to plot your own course, to live your own life while you are wrapped up in what your spouse is doing. There is also the pain that inevitably comes when you see something that is not a step homewards. Would my own life be different if I paid no mind to what my W was up to? Absolutely. Very likely I would be divorced right now rather than clinging to an uncertain and intangible hope. Has the very real pain that I have suffered by snooping been worth this connection? I don't know the answer to that. That part of the story hasn't been written yet.
I have been staring at the screen trying to write an appropriate wrap-up paragraph. I can't. There is no magic pill that will make it all better or go away. There is only the journey and the choices we make along the way. Tracks in the snow are ephemeral and vanish with the fresh snowfall and the spring.
On BD H52, W50 T27, M26 S21, D23 BD-9-Mar-16 D-15-Jan-18 Final-19-Apr-18 I am a storyteller. The story may do you no good. But a story is never for the listener. It is always for the one who tells