Absent

Absent is a 2011 erotic thriller film directed by Argentine director Marco Berger. The film centers on a recently engaged, 30-something male swimming instructor who is thrown into emotional turmoil as he repress his desire for his 16-year-old male student, who shows sexual interest in him, and engages in overt advances towards him.

Synopsis from Wikipedia, CC BY-SA 4.0. Everything below written here.

Poster © the film's rights holders.