LOL sounds like you didn't even watch the movie, you just read a bunch of mad tumblr reactions. If you had watched it and paid attention, you'd have seen that Gamora rejected Peter multiple times (and whether or not they get together in the future, Peter seemed fine with not hooking up with her), they didn't get together at the end, she had her own arc of betraying Thanos, her conflict with Nebula, deciding what to do with the stone, identity issues, and she actively played a part in planning/infiltrating Ronan's ship. If she hadn't stolen the gem from Peter, everyone would have died in quick succession. But no she was useless and only there to be saved by the hero. Ugh fandom.