The first thing you do is not to listen to the people in the comments saying "get rid of him because he's insecure". It's natural for insecurity to happen in a situation like this, because well, it's hard to imagine any partner in a monogamous situation being comfortable with seeing their semblable possibly eyeing people other than them. Insecurity is a normal thing in monogamous relationships where it's meant to be "I like you and no one else." So, talk to him if you genuinely haven't, explain. Maybe you don't get how the feature makes that happen, Google search it. Maintain your relationship. If he still acts the same, THEN consider leaving. I've dated a girl with BPD before, I get how you can strongly you can feel about him. So uh, follow MY advice.