Angsty version:

Amy learns very early on about her gift, as it’s rare but not unheard of. She’s precocious about it; when she’s five, she’s prone to doing things like seeing happy couples with unconnected strings and bluntly saying, “You’re bad for each other.” Naturally, Amy’s mother is mortified by this behavior and urges her to stop doing it.

At first, this seems like a normal reaction...until one night at dinner when Amy asks, “Mom, Dad, why aren’t your strings attached? Mom is attached to the mailman instead.”

That’s how the truth comes out that her mom is cheating on her dad, which leads to their divorce. Amy blames herself, and her parents don’t do a very good job of convincing her otherwise. The resentment’s there, and she can tell. From then on, she resolves never to share her gift–her curse–with anyone for fear of ruining something else.

This continues until she hears two good friends of hers talking. One is trying to defend her clearly abusive partner, saying he’s “not always like that,” he’s “usually very sweet,” etc. And Amy just can’t hold it in any longer. She blurts out that they’re not meant to be together. The one she belongs with is the best friend who brought her in, the man who’s holding her as she’s speaking. Everyone’s silent for a moment, and Amy immediately regrets it...until six months later, when the two are dating and thank her for stepping in.

Amy embraces her gift at last and uses it to help others, becoming a matchmaker and relationship therapist. However, she spends just as much time “matchbreaking,” carefully working to break up couples who are bad for each other. She learns that sometimes, the best way to spread love is by ending ties that pull in the wrong direction, like pruning a plant of old leaves to allow new ones to thrive. It’s hard sometimes, but there’s no one who’s better at it.

Her mother never makes amends, but her father apologizes profusely for how he treated her when she was younger and introduces her to her new stepmom, thanking her for giving him the opportunity to meet her.

--

Now, the happier option:

Amy can see the strings tying people to their soulmates. Aside from aromantics like Sonic, who have little knots/bows on their fingers to show they’re complete on their own, everyone has a string...except for Amy herself. Hurt but determined, she decides to start a matchmaking business to spread love around the world in her own way, even if she can’t be a part of it.

Then, she meets Shadow, the only other person she’s met without a string. He brushes off her concern, as he doesn’t put stock in the concept and has reluctantly resigned himself to being a “dead end,” but Amy insists on trying to match him up with his soulmate all the same, as she feels everyone who wants a soulmate must have one. She finds it’s not so easy without the cheat sheet she’s had all her life. While getting to know Shadow and considering all the wonderful things he could offer as a partner, she can’t help but fall for him herself. Likewise, Shadow sees all the care and effort she’s put into bringing him happiness and fulfillment, the passion and devotion no one else could ever match. He doesn’t stand a chance, either. Amy takes the plunge and gets together with him even without that divine confirmation.