Reluctant Dependency - One Lead Needs the Other

1 - ML has a severe aversion to physical contact with anyone except the FL

1 - FL's kiss cures the ML's illness

1 - ML's sensory perception depends on him touching the FL

1 - ML has a severe aversion to physical contact with anyone except the FL

1 - FL's kiss is the antidote to the ML's weird supernatural curse

1 - FL's curse is relieved by touching ML

1 - FL is the only person the ML can stand to be around (because he's scared of people and thinks she's a robot)

1 - FL is immune to the ML's time-stopping ability

1 - (kind of a slowburn but) FL is the only person ML can touch without triggering his mysophobia

1 - FL's blood is the cure to ML's illness

1 - FL's disease can only be cured by kissing ML (or his half-brother)

1 - ML is the only one who can recognize FL even when she switches into a different body

1 - ML can only touch FL

1 - when ML eats ice cream made by the FL, his communication disability is relieved

1 iirc - FL has social anxiety but it doesn't act up around the ML

1 - only the ML can hear/see the FL

1 - ML is the only one who can extend the FL's dwindling lifespan

1 - ML's blindness is cured when he kisses FL

1 - ML cannot touch women except for the FL

1 - FL makes perfume that cures ML's colorblindness

1 - ML has face blindness but can recognize the FL

1 - only the FL can cure the ML's ED (yes, that kind of ED... -_-)

1 - ML has social anxiety, FL is the only one he's comfortable with

1a 

FL is also the only one who knows about the ML's mind-reading ability, and she needs him to solve her court cases occasionally. 

1a

1a

1a

1a

1a

1a

2 - ML needs FL to end his curse because she is his destined bride

2 - ML cannot get his inheritance unless the FL specifically agrees to marry him

2 - ML needs FL to use as a "human talisman" to ward off bad fortune

2 - FL thinks that the only way to cure her bad luck curse is by sleeping with the ML

2 - FL is the only one who can end the ML's curse (plus, he's bound to her via a love spell)

2 - ML needs the FL's knowledge of the future

2 - FL needs the ML's scent to gain power

2 - FL has access to the cure to the ML's terminal illness

2 - FL needs to touch ML's necklace to shift into human form

2 - FL possesses the cure to a poison that's slowly killing the ML

2 - FL cures the ML's color blindness (among other things)

2 - FL has the ability to see other's memories, which the ML needs to solve his amnesia

2 - ML(s) need FL's magic blessing to win a war

2 - FL's kiss cures poison, ML gets poisoned a lot

2 - ML helps FL regain her memory

2 - due to an old family curse the FL is bound to help/serve the ML

2 - ML needs to help FL find true love in order to return home

2 - ML thinks that by marrying the FL, he can prevent a doomed future

1 - FL's blood can heal/cure people, it heals both SMLs at various points

3 - FL binds first the ML then the SML to feel all pain she feels through a poisonous bug

3 - demon ML is magically bound to help the human FL whenever she needs it

3 - ML is magically bound to feel FL's injury/pain in her place

3 - human FL swallows the gumiho ML's "bead" which he needs to turn human

 3 - FL swallows an object that the ML needs to cure himself. he must make her fall in love with him to transfer it back

3 - ML & FL become magically bound so that whenever the FL is in pain, the ML will feel it

3 - ML's demon power is accidentally transferred to the FL

3 - ML is bound to obey the FL due to her "heroine aura"

3 - FL has to kiss ML to stop turning into a dog after accidentally kissing him once

3 - FL was blind but acquired the ML's vision

3 and 4 - FL takes ML's good fortune and ML receives FL's bad fortune

3 and 4 ish - I won't elaborate to avoid major spoilers

4 - FL has to shock the ML basically to be able to return to her own world. Later on, the ML also needs the FL to come to the real world iirc

4 - FL feels ML's pain, ML feels FL's emotions

4 - FL stops being haunted by ghosts when she touches the ML; ML needs FL's unique ghost-seeing ability to help him banish a ghost

4 - FL and ML trade their sense of taste when they kiss

4 - FL needs ML's magical energy to regain her own power. ML needs FL to teach him magic because no one else will.