WARNING: The following contains spoilers for Avengers: Infinity War and Marvel's Thanos comic series.
Marvel's 2012 blockbuster The Avengers ended with the revelation that Thanos was actually "the Other" behind Loki's schemes and the Chitauri invasion of New York City. Challenging Earth's Mightiest Heroes was to "court death," he concluded, and that made the Mad Titan smile wickedly.
Since his introduction in 1973 in Marvel Comics' Iron Man #55, by Mike Friedrich and Jim Starlin, the cosmic tyrant has wanted only one thing: love. Specifically, that of the living embodiment of Death, who in the Marvel Universe takes many forms, from a pale woman in a dark robe to, well, a pale woman in a dark robe, but with a skull for a face. Thanos has undertaken many genocidal quests in the hope that she'll finally give him the attention he so desperately craves. Despite all of those attempts, Death isn't really that into him, yet she still accepts his murders, as she deals in souls.
Perhaps the most famous example of how far he'll go occurs in the 1991 Marvel Comics miniseries The Infinity Gauntlet, by Jim Starlin, George Pérez and Ron Lim, in which Thanos demonstrates his commitment to Death that he wipes out half of all life in the universe. For much of the build-up to Marvel's Infinity War, it was widely assumed the Mad Titan would again be motivated by his courtship of Death (or perhaps even Hela, as played by Cate Blanchett in Thor: Ragnarok). But shortly before the film's release, directors Joe and Anthony Russo clarified that Lady Death wouldn't make an appearance. That may be the smartest decision the filmmakers could have made.
To be clear, the idea of the Mad Titan doing what he does on is own volition isn't exactly new. The recently concluded run of Marvel's Thanos comic, by Donny Cates and Geoff Shaw, depicted the character has finally giving up any hope of trying to earn Death's love, even as his future self, the king of a destroyed universe, still hopelessly pines for her. King Thanos' sole purpose for bringing his younger self to the future is to finally kill the last living being in the universe, the Silver Surfer, as a final way of winning Death's affections. Even when Thanos meets Death in the far future and has to fight his older self to survive, he becomes determined to avoid the pitiful fate he witnessed. To do that, in some way, he'll have to continue to renounce Death.
By doing away with the creepy love-story element in Infinity War, Thanos is permitted to be his own monster without all the weird baggage. Love is a powerful motivator, sure, but some acts are just a bridge too far, and genocide would be one of them, especially when our first sight of Thanos in the film shows him surrounded by the bodies of Asgardians. There was never any real way to justify the acts of a mass murderer if he was doing all of this simply to impress a love interest. However, his desire to prevent overpopulation, and save the universe from the same grim fate that befell is home world, makes a little more sense. His intentions are noble, if unquestionably misguided. If nothing else, Marvel Studios would've had a difficult time making audiences comprehend why he'd be "rewarded" with seeing the object of his affections torturing and killing his daughters, especially when flashbacks demonstrated that sacrificing Gamora wasn't an easy decision for him.
No, Thanos doesn't love Death in the MCU, and for all we know, she's not even exist in this universe. Here's hoping she never does, because including her defangs one of the greatest villains in the film franchise. Thanos was worth the six-year wait, and he doesn't need to prove himself to anyone. He's much scarier when he's acting on his own accord.
Directed by Joe and Anthony Russo, Avengers: Infinity War stars Robert Downey Jr., Chris Evans, Chris Hemsworth, Mark Ruffalo, Jeremy Renner, Scarlett Johansson, Paul Bettany, Anthony Mackie, Paul Rudd, Elizabeth Olsen, Tom Holland, Benedict Cumberbatch, Chadwick Boseman, Chris Pratt, Zoe Saldana, Dave Bautista, Bradley Cooper, Vin Diesel, Tom Hiddleston and Josh Brolin.