Does a same-sex marriage count as being "married" to the abuser for immigration purposes?
Yes. A marriage is valid under immigration law if it is valid in the jurisdiction where it took place. Now that the U.S. Supreme Court has ruled that it is unconstitutional for states to ban same-sex marriages,* any valid same-sex marriage performed in the United States should be recognized by USCIS (Immigration).
* Obergefell v. Hodges, 576 U.S. ___ (2015)