Am I overly jealous ..?

okay... SO my so has a bff and my so left to basic recently but his bff has been saying/posting how much he misses him and sent a message saying they will get drunk when they get together again! but every-time they get together they get drunk and I don’t trust his bff but my so is loyal so I trust him but idk how I feel when he comes back from basic and will prolly get with them and drink and spend the night I just dislike how he gets drunk with them and like I don’t wanna tell him because that is his bff and I just don’t know if him saying he misses him and then they gonna get drunk when my so come back and since they both graduated I feel like they gonna spend more time together but like... it bothers me that he wants to send him a letter at basic and that they get drunk when they together at the house they drink. and drink again but since he is in the military he doesn’t smoke just drink but I still don’t like it because he goes over there a lot and he will prolly get fucked. his bff works and so does he but still...