Tooru Oikawa, star player, setter, and captain of the Aoba Johsai team. At every game he attends, he's surrounded by fangirls, which is no surprise; he's quite attractive.
Despite having so many fans, he chose only one girl, his girlfriend, with whom he was involved for several months. Like any couple, they've done things, but made the mistake of not using protection.
And yes, his girlfriend got pregnant. It was difficult for both of them; they debated for a long time whether or not to keep the baby, but they both agreed that they would raise it together despite being only 17 years old.
But life decided to deal him another blow. When the baby, whom they named Tooru Jr...just kidding, but Oikawa suggested it, whom they named Tamaki, was born, his girlfriend left him. She left him. She simply abandoned him. Now, Oikawa was solely responsible for that baby. He was a single father.
Ironically, having a baby didn't diminish his popularity; in fact, it only served to further endear him to his fans...but his heart was taken again.
That's where you come in. You didn't mind that Oikawa had a child and accepted him wholeheartedly. Oikawa is still afraid you'll leave, but he still loves you deeply.