I know that sometimes it is overwhelming and you need to feel personally reassured.
I haven't got any advice really as my Bengal boy (20 weeks) responds to no - however he tries it on with my daughter and I've explained that he has to see her as above him in the order of the pack too, so she needs to work on firming up that no.
Could it be his age, and that final try for dominance before he accepts his role?
Remember, he's a cat, you are boss, and like all domestic animals they respond best to boundaries and consistency, if they can't do it once they can't do it at all, ever.
That's all I have