Of course, my partner and I also exchange accounts. Maybe because we have almost the same properties. I'm not even willing to see her staring at another woman.
You are in a stuffed up relation i guess,you do not trust you partner and you are really insecure and so is the reason you are doing these kind of staking behavior 
,you have to give a breathing space to your partner ,he or she needs to have their own privacy ,having committed to someone does not mean that you have to peep into everything,unless you partner does not bother ,then it is your call,but i would not go into others personal things like e mail and phone.