Its called your fart comfort zone, you only fart around people you like, love or trust. Why, because every once in a while every one has to let one go and if you have to watch your self all the time you may hurt yourself, well at least it will feel that way. So if your boyfriend or girlfriend passes some gas while your around just think of it as a sign that your relationship has hit a new level. This may be good or bad, it could be a sign of commitment or an indicator that things are getting to serious and you need to get out.