The fact that we, ourselves, get to the point of playing detective in these ways is indicative of a MAJOR problem in the relationship. It really indicates a severe lack of communication. If you are doing all you can to have a productive dialog about where you stand in the relationship, yet still remain unconvinced, so much so that you feel the need to violate your partner's privacy (whether it is ultimately justified or not)... .that is a major sign that you should consider disengaging to see what happens, rather than becoming a paranoid detective and doing things you'll later regret. We do have a choice to go down that road or to disengage. I really don't ever want to stoop to that level again and if I feel myself going there I intend to give my head a shake and make a different choice as to how I respond.
While I believe that in this day and age, a couple should be transparent and share passwords during the relationship, I also agree with the above. If the sharing isn't for convenience sake or accessed for two-way assurance (both parties aware of the checking) after a fight, but rather is being accessed while you're playing detective, something is wrong. Been there, done that. I put myself in the role of 'babysitting' my STBX. I found it so exhausting that I just had to quit. I told myself, "If fate has something I need to see, it will show me." And it did, at exactly the right time. The motto is, "Take care of yourself," not watch your back every second of every day.
If I had the temptation to access an ex's email because I had their password, I'd politely send them an email asking them to change their password, stating it would make me more comfortable if I no longer had it. The less explanation the better.
Would I really? Yes, recently my STBX was on the phone with his mom. I could overhear him, so I was tempted to eavesdrop. Then I realized I was playing dectective again, so I knocked on the door and let him know that I could overhear him -- so he had the option to continue the conversation from a different place. It's HARD, but it's part of taking care of yourself. Otherwise, their actions will continue to hurt you. Do you really need any more pain?
Not judging though.
Been there, done that
. Checking text messages, phone logs, email, blocking 'platonic' friends (LOL). We finally agreed together that text messaging had to go. Except for communications with my ex (for visitation), texts are blocked.