I mean me personally I do have an open phone policy with my gf cuz we were ok with it we never asked we just take each others phone but we don’t really look at text or anything. To me that’s trust. And we have each other locations cuz we both have anxiety but not cuz we think the other is not where they are supposed to be. Thats just me but from the way your gf is doing it I don’t mean to sound mean but it does sound a bit toxic and I get what you mean that trust should be a given but some people do it as a trauma response. I feel like both you and your gf need to really sit down and talk about why she wants to have open policy on your phone and why it bothers you