Is doubting the truth of Christianity enough to make a proximate occasion of sin necessary?

Is doubting the truth of Christianity enough to make a proximate occasion of sin necessary (rather than free)? For example, imagine Bob is subject to many proximate occasions of sin against the 6th commandment. He could alter his lifestyle to remove these occasions of sin, however he is also not quite convinced that Catholicism (or even Christianity) is true. But in his situation there is no way for him to continue his inquiries without the danger of these occasions of sin. Does the danger to faith make these occasions of sin necessary and thus permissible?