I hear you on the snooping thing. I did that when my husband started hiding his cell phone. Looking back I probably should have let the whole thing go, but I was obsessed with getting information.... still am
The best way to deal with the jealousy, fear. etc... is to start GALing and begin some 180s. Start working out at the gym more, buy some new clothes, focus more on yourself.... Ask her a million impersonal questions when she's around... i.e. how's work? how do your feel about that? What do you think of? Don't blame, don't criticize, practice being an amazing listener and reflecting her words so she feels you're really listening. Show caring and concern in a friendly way that's not smothering. Give her space as well. There's a chance she could be in some type of MLC and detaching and working on yourself would be a healthy way to deal with this.
There is no arriving, ever. It is all a continual becoming.