I don't know this story, prior to this movie, but I could've sworn that Eddie Brock was an astronaut or something like that....and wasn't he dating Gwen Stacey or something???
A few different versions here. In Spider-Man 3, he dated Gwen Stacy, but not in the comics. In the comic books, there was an astronaut, it was J. Jonah Jameson's son John Jonah Jameson III. He dated Mary Jane, and he later became the villain Man-Wolf after returning from space.
Eddie's whole story was he did shady dealings and lied about Spider-man in one of his articles, it blew up in his face and he got fired for it. He blamed Spider-Man. When Spider-Man rejected the symbiote, it latched onto Eddie Brock and they became Venom.