I think you need to work on what ever is causing these insecurities of yours instead of trying to lay the blame at your girlfriends feet.

Most women these days have a sexual history.

Most men don't care. In fact some of them care so little that they are now happily raising another man's child.

If you can't deal with your girlfriends history to a point where you feel the need to be so possessive and interfering as to require her passwords and details of things that are none of your business then you need to let her get on with her life and work yours out.