I believe story was written between 1950-1970. I read it in a large paperback anthology in the 1980s. It was a short story - deep space encounter with alien intelligence. The first astronaut to experience alien presence is sublimely moved. Back on human spaceship doubts are raised - have the aliens bewitched the astronaut? Final revelation is that aliens & humans complement one another, become as one and both species reborn into new life.