I am writing a story that revolves around a number of characters that have superhuman abilities living amongst normal people, akin to they myriad superhero comics or many urban fantasies out there (e.g., The Mortal Instruments, many shonen manga). The main romantic relationship in this story focuses on two people with powers: one of whom is abnormally powerful due to being the protagonist and the other having powers that are dramatically less combat-oriented. The thing is, the very nature of superpowers in this universe destabilizes people's minds and often results in various mental disorders. As if super strength came with a side order of the autism spectrum, major depressive disorder, schizophrenia, or borderline personality disorder. The protagonist in particular is extremely emotionally repressed but has problems with impulse control and PTSD from their traumatic experiences dealing with the supernatural. Think the Hulk.
The two are supposed to have a loving, supportive, emotionally healthy relationship. The problem is that I realized there is a huge issue with the unequal nature of their pairing, and their relationship reeks of potential physical or emotional abuse. The protagonist can tear a car in half with their bare hands, and their partner...can't. What does this mean in their relationship when they want something and their partner says "no"? What happens when they get angry or get in a fight with their partner, is it safe for their partner to be around them? And because the characters are not morally perfect and are shown to have real flaws and psychological issues makes that threat rather than just a mere hypothetical.
Larry Niven's Man of Steel, Woman of Kleenex goes into the aspects of the inequality when it comes to the physically intimate aspects of a relationship, but in this case I'm more concerned about the psychological ones. Unequal pairings are hugely frowned upon in real life (examples such as teacher-student or boss-employee relationships), and as a result a relationship like this is not seen as cutesy by modern audiences and they will not root for it. It waves so many red flags the characters might as well be talking in semaphore. It's true this kind of relationship is very common in fantasy fiction: Superman and Lois Lane, Spider-Man and Mary Jane, etc. The thing about Superman is that he is such a big blue boy scout that it seems completely inconceivable that he would ever abuse the massive physical advantage he has over Lois Lane. And even then numerous Elseworlds have pointed out the potential problems in their relationship if Superman wasn't morally perfect. Homelander in The Boys is another good example of the potential horrors in these kinds of relationships, but in that case Homelander is explicitly framed as a villainous character rather than someone the audience is meant to root for. The Hulk and Betty Ross might be a more apt example, but in this case the potential issues...just never come up (which is weird given that Bruce Banner grew up in an explicitly abusive household where his father murdered his mother). Another good example in a setting with lower power scaling might be Bella and Edward from Twilight. Edward is horribly abusive, and Bella is so weak compared to him that she can't do anything to stop his abusive behavior.
The other character is the emotionally dominant one who "wears the pants" in the relationship, but in turn this makes the main character look like a doormat who can't stand up for themselves and paints their lack of assertiveness and independence as a good thing, rather than the two having a mutually healthy partnership.
The bluntest, simplest answer to this question I can think of is "people with powers should not have romantic relationships because of this inherently unequal power dynamic, or they should be restricted to having romantic relationships with those with similar powersets where there is no inequality". The problem with this is that it sends a message that people with psychological problems do not deserve love and support which is...a pretty bad message to send. It's made even worse in that the other character has powers of their own, so it sends the message that the character cannot even have a relationship with other superhumans, they have to be restricted to the few hyper-powerful superhumans that are on their level. And that, at best, sends numerous messages of ubermenschen or being "the lonely god-like elite" which is...also not good.
Given these issues, how do I write a romantic relationship between two characters where both are flawed individuals and one is significantly more physically powerful than the other?