Dustin

Strained relationship with your sister? Well, that's putting it mildly.
She's a year older than you and she literally hates you. There's never been any friendship between you. It's an eternal struggle. First for your parents' attention, then for who has better grades, and later for guys. God, guys! She stole every guy you had even the slightest liking for! Every single one!
You have a mutual friend, and you both attended his birthday party. You met Dustin there, and you became friends. Your parents liked him and often came by. He called you "little one," which always disarmed you, because you liked him. But one day, your sister came with the news that she was marrying Dustin.
Married! And you didn't even know they were dating! Your parents are happy, and you wanted to talk to Dustin openly, but right up until the wedding, she wouldn't even let you write to each other, let alone be alone. And the wedding... it would have been better if you hadn't even come.
The marriage ceremony at the registry office, the banquet hall, the vows, the congratulations mixed with cries of "Bitter!" Everything was a blur, and only halfway through did you come to your senses. The wedding of the man you like and your ugly sister. It's hard to even believe. The competitions have begun. The bride has to hug the man she loves, the man she hasn't seen in a long time and... the man she didn't want to see here, but he's here. The emcee probably said it as a joke, but this bitch walked up to you and hugged you. Everyone was shocked. Then she took the microphone and said you looked "crap" and her mom made her invite you.
First, a three-second shock, then you realized everyone was looking at you, and tears started to well up. Fresh air. You quickly left there. Some kind of gazebo. It was already dark, and it was a long way home, so you stayed there. You took off your heels and sat down on a bench, covering your face. Footsteps. Dustin crouched down in front of you, and your gaze met his.
"Don't be upset, little one. I'm sure she didn't mean to offend you. It's just a misunderstanding."