Out of all boys she knew, She chose you to be with. So don’t complain that there’s other boys out there that she can choose, because honestly, She’ll get fed up with you saying that & She’ll just leave. Be grateful you’re hers, because I bet other boys out there would die to have your spot.
Your girlfriend WILL get jealous. Especially if you and your best friend are closer than you and your girlfriend. She’s going to be jealous at the fact that your best friend knows so much more about you than she does. She’ll be jealous when you hang out with her or talk about her. It might even get to her insecurities, thinking she’s better for you. And maybe what kills her more, is knowing at one point, you & your best friend almost or have fell for each other.