Amazing Girl considers breaking up with Bob, but decides to stay with him come what may.
She breaks up with him until she knows for sure he's safe.
Doubly Subverted: She just said that; she ends up breaking up with him after all.
Amazing Girl breaks up with Bob despite the fact that he is also a superhero who is more than capable of defending himself against any attacks.
Amazing Girl breaks up with Bob to protect her enemies from him.
Zig Zagged: Amazing Girl keeps changing her mind about whether she and Bob are together or not.
Averted: Amazing Girl and Bob are in a steady relationship, but this issue is never brought up.
Enforced: "It sure would be a grand romantic gesture if Amazing Girl gave up the man she loved in order to protect him from her enemies; plus, it'd make her angsty, and everyone knows that True Art Is Angsty."
Lampshaded: "If we stay together, they'll find you and kill you. And if that happened, I'd never forgive myself."
From the outset of the relationship Amazing Girl warns Bob that she may break up with him due to this trope.
Alternatively, Amazing Girl wants to break up with Bob anyhow, and uses her enemies as a convenient excuse.
Exploited: The villain looks for past romance partners as well as present, knowing that do-gooders so often perform this trope.
Amazing Girl actively cultivates superficial relationships, one-night-stands and relationships without romantic involvement precisely so that she never finds herself in this position.
Alternatively, Amazing Girl is a Celibate Heroine. Even when she might want to love like a normal person, she's conscious that heroes must make sacrifices to ensure world's well-being.
Or Bob just points out that if Amazing Girl dumps him, he'll still be a likely target for villains, and now he won't have an awesome superhero girlfriend around to save his sorry ass.
Discussed: "Bob has been devastated since Amazing Girl dumped him, but he'll recover when he realizes it has been a blessing in disguise. Living as a super-villain's recurrent hostage is no life for anyone."
Amazing Girl hasn't actually solved the problem; those enemies who suspect that Bob is special to her are not going to leave him alone simply because she has made a token gesture in separating from him, thus still leaving Bob in danger. All she has done is cause her and Bob heartache and loneliness.
Or, the bad guys aren't really concerned about whether or not Amazing Girl and Bob are currently in a relationship. Despite Amazing Girl's efforts to protect Bob by breaking up with him, they kill himanyway.