Replying to Jealousy

So I have a girlfriend of half a year and there is this other guy who is one of my best friends and one of her best friends. And before we started dating a lot of people thought that they were gonna date and he always thought she was really pretty. But now we are and for the most part, are extremely happy. However her and this guy are best friends on snapchat and she tells me about deep talks that they have and I am not super jealous but slightly concerned. An it's not that I don't trust her and I don't want to be some overly protective boyfriend. But I have little feelings of jealousy inside that I'm not sure what to do with. Please give serious advice only