It would appear to be Una vez, un hombre (One time, a man), a 1970 Mexican movie.
Here's my translation of this Spanish summary:
Daniel, a worker in a plastic toy factory, gives the defective toys to Raúl, the foreman's young son; the foreman reprimands him for it. The child dies and Daniel reproaches the father for forgetting him quickly after.
Don Felipe, owner of a marble shop, becomes friends with Daniel when he sees his sadness and shows him his astrology device, as he is a passionate, and lets him see through a telescope of his invention a planet where the three Fates (Clotilde, Laura and Antropina) are, watching the life of men with a projector, and cutting the films as they wish.
Felipe proposes to Daniel to throw him to destroy the machine. Daniel prepares for the trip and his wife is alarmed. He earns a reputation as a clairvoyant when he sees the projector and provokes scandals, but in the end he arrives at the Fates' location, and pretending to repair the projector, he puts his wife's film after all the others and returns to Earth. Only the children see him arrive. He destroys Don Felipe's device and tells him that the most valuable thing of all is love. Then he finds out that he will have a son.
There is very little on that movie online (there's even no English results that I know of, for that matter), so here are the only two images I can seem to find:
Found with the Google query
pelicula fantastica "tres parcas" (
fantasy movie "three fates"), which returned this review as the first answer.