Has she perhaps had negative experience with say a previous partner for having such distrust? What are her own habits regarding electronic devices and social media? What kind of time are you spending? And how much of this is done in her presence?

Is there room in the relationship for a give and take regarding boundaries? Are you both able to make concessions to find a common ground?

My boyfriend and I have made some agreements regarding boundaries when it comes to texting and social media. Of course I still get uncomfortable but I need to trust. We have also agreed that neither of us will use our cell phones at all in the other's presence. This has come from hurt feelings on both sides that whatever has our attention on our phones has apparently taken priority over the other person.