Why is he comfortable with farting around me ?

My boyfriend has gotten really comfortable and just farts sometimes when we’re together, what does this mean ? Does this mean he is way too comfortable, or is it a sign of disrespect? We’ve been together for one year and a month, and it feels like we’re a married couple. He doesn’t do it a lot, but he does it more now than when we first met. He smiles when he does it, and it’s just of funny.