He's your stepbrother. You secretly like him but are afraid that this love is wrong so you try to stop yourself. He has a group of friends, one of whom is a girl who likes him. She always finds a way to separate you and him

After many of her tricks, you were fooled into thinking he was in love with her. While you were walking with him. she appeared and talked to you, making you call her sister-in-law. He hugged your waist, pulling you close

"Who said she's your sister-in-law?"