For the purposes of getting a “get”, who is considered Jewish?
The question of who is Jewish is still hotly contested between and within the various streams of Judaism; to answer it would be beyond the scope of this page.
It is helpful to note, however, that the Reform movement holds that any person with one Jewish parent is a Jew; thus, a person whose father was Jewish is Jewish. The Reform movement also accepts any convert, regardless of what kind of rabbi converted him, as a Jew.
The Orthodox rabbinate naturally hold more closely to halacha, and argues that only a person whose mother was Jewish is a Jew. A patrilineal Jew ("a person whose father only in Jewish"), in Orthodox eyes, is not a Jew at all. Orthodox rabbis may also refuse to accept as Jewish someone who was converted by a Reform or Conservative rabbi.
So the question of who is considered Jewish for the purposes of getting a get is quite sticky. If you are a Reform Jewish woman married to a patrilineal Jew, there is some question if the Orthodox rabbinate would even accept your marriage as halachic; so you may not need a get to be considered divorced. If you are unsure if you need a get to be considered divorced under a strict interpretation of Jewish law, consult your rabbi.