I highly recommend a new film, Keep the Lights On, directed by Ira Sachs. It concerns a ten-year relationship between two men in Greenwich Village. Erik is a documentary film maker living precariously on money from his father. Yet through sheer perseverance he succeeds professionally. Paul has a good job with a publisher. Over time, Erik proves the stable one, because Paul is a crack addict who disappears for weeks at a time on drug binges. 

One marvels at Erik's saintly patience, yet in the end one has to wonder whether it isn't his possessiveness that keeps driving Paul away. In short, the film is about the strains that afflict almost any serious, long-term relationship nowadays. 

Unlike the general run of gay films, with their formulaic plots, Keep the Lights On seems like real life. However, a truism holds that art imitates art.  In this case the model seems to be that superb analysis of alcoholism, Days of Wine and Roses. http://keepthelightsonfilm.com/