True and untrue- due to the high rate of relapse- people in NA have a smaller percentage of long term sober people that can positively influence OP's partner. Therefore AA is a better option- even though her DOC is heroin. It's still relatable. And completely acceptable.

And it would help (if you do decide to have her go to meetings)- to go to AA meetings in "nicer" neighborhoods. No offense intended- people who have/access to a higher income- in no way means they have a higher chance of recovery- but that money does mean they can get access to more treatment plans and facilities.

Your partner will be around people who have had longer sober time (10-20 years of sobriety) & who are LESS (not entirely. Just marginally less) likely to meet somewhere only to trade drug dealer's contacts with each other afterwards.

Your partner is more likely to find a sponsor there too.