What Causes Saliva Odor?

hello ive got a real big problem in here i have an oral sex with my bf for a long time. .. actually everytime.. then for this past few weeks i can notice that the smell of my saliva stinks i know saliva has that not so good odor ...but this one this really stinks but my breathe is just fine. this is so unusual because i go for regular check ups to my dentist... could this be cause of the oral sex or even kissing?