No nudity at all. Sex is implied, but never shown, and never talked about. In one scene, Nikander returns to Ilona just after she has taken a shower and is wearing a bathrobe. He grabs her, she throws her arms around him, and they kiss. In another scene, the two are sitting on the beach, fully clothed. when suddenly he pushes her onto the ground and kisses her. That is as passionate as the movie gets.
It is also strongly implied that another man has been either having an affair with Ilona or at least trying to get her to sleep with him.