1. Tony Stark (Iron Man) and Pepper Potts
There you have Tony Stark, a.k.a. Iron Man, flying around in his shiny armor, saving the world from one catastrophe after another. Then, cut to Pepper Potts, his better half, who often finds herself in the not-so-enviable position of waiting for Tony to swoop in and save the day. This dynamic has rubbed some fans the wrong way, making them feel like they're watching a rerun of an old-school damsel-in-distress movie. It's like, "Hey, we get it, Tony's the hero, but can Pepper get a piece of the action without being tied to the train tracks waiting for a rescue?"
Now, don't get me wrong, Pepper does have her moments where she's out there kicking some serious butt, especially when she suits up in Avengers: Endgame. But for a good chunk of the MCU, her role felt a bit like she was just there to make Tony look good or give him a reason to invent something new to save her. It's always felt like their relationship was out of convenience instead of passion if that makes sense. That's been my personal issue with the Tony-and-Pepper love saga - it felt like Tony only really wanted her because she'd been doing everything for him as his secretary to begin with. But I do have to admit that towards the end, especially in Infinity War and Endgame, it did feel like a genuine relationship. Who knows, maybe Tony had to grow up and be a man instead of a pretty and rich boy.
TL;DR - It's not that they don't love a good love story - I just wish it wasn't so... vintage in its execution. But hey, every superhero needs their grounding force, and Pepper surely keeps Tony's feet (and heart) firmly planted on the ground—when he's not flying off to save the world, that is.