An arty little relationship film, Austin Chick’s XX/XY is ultranaturalistic thanks to some fine performances (especially by the always compelling Ruffalo) and some very dark lighting (which can make it hard to tell what’s going on). Ruffalo plays Coles, an animator/adman who falls for pretty party girl Sam (Stange). They also have an on-and-off menage a trois with Thea (Kathleen Robertson). Coles later settles down with Claire (Petra Wright), but a chance encounter with Sam threatens their domestic bliss. Like a relationship, XX/XY isn’t always thrilling; unlike recent Hollywood blockbusters, however, it is at least in touch with reality. EXTRAS Just a couple trailers and Spanish subtitles.