my boyfriends stupid friends

All of my boyfriends friends are so stupid. They keep telling him theres no way beig long distance that im not cheating. He gets upset and i keep reassuring theres no way i could ever do that to you. Its just so frustrating because he doesnt take it lightly. I try reminding him thats why we are good at long distance and all but it is rough. Why would they tell him this? Hes happy with me so just let him be? I dont understand are the saying that its shocking i would stay with him? They dont know me ive only been introduced once and all. Its just we've been together 3+ years and these are his "good friends" and i told him if we get married i am not inviting such negative people.