Although Romeo's last name is Salvatci-Romano, his parents never actually married. They couldn't, it'd be too much scrutiny for Francesco Romano, CEO of one of the most prominent wizarding companies in the Wizarding World. It wasn't his fault he'd fallen in love with Giorgia, a vampire hailing from Korea who had stolen the identity of the mistress of her ex-lover after she murdered her. Giorgia was as beautiful as a sunset, and her personality perfectly contrasted Francesco's own in the way that made them a perfect match. Even though they'd been in love for years, dating in secret, it was the reality that they'd never be able to have the dream of a family in a luxurious home on the coast of Italy that made them attempt to separate.
Because it never happened.
Francesco eventually married Giorgia's non-vampire sister whose name was Aurora, but there was no true love between them. Their relationship was purely business and their endeavors were completely separate. Under this premise, Francesco continued his relationship with Giorgia, even moving him into a mansion on the coast of Italy just like they had planned if they were to ever have a normal life together. He stayed there most of the time while Aurora and her lover stayed in Francesco's penthouse in Rome. It became slightly stressful on the two, however, because Giorgia could never be seen when she leaves and Francesco had to provide explanation constantly for why he and his wife were always separated.
The two eventually had a child, which they named Alessio Feliciano Byungjin Salvatci-Romano. They gave him both their last names to show that they were truly unified by this child, and his names tied into how much he meant to them. The defender of their love, that's why he was named Alessio. They were lucky to have him, Feliciano. He was precious to them, a luminous star, Byungjin. There was so much thought and planning put into having this baby boy, it was no wonder he was sheltered and protected so much as a child.
4 years after they had Alessio they had a baby boy, Romeo, who was a spunky and energetic little boy from birth. Despite his attitude, it wasn't a good fit for the lifestyle that he was forced to live from infancy. Unlike Alessio who was naive and followed everything to a T, Romeo was the opposite. He always tried to defy his parents and not listen to them, breaking rules and getting into trouble and trying to escape their home to see the outside world. You could almost say it was a Rapunzel type of situation, save for the blind obedience.
Because of this he had his magical experience at age 7 when Alessio was sent off to Hogwarts, leaving no one but the maids and butlers to try and somehow control this wild and fiery kid. Romeo had managed to slip past them and even the few guards around the house, slipping outside into the backyard to be free and play in the open air. Only, this didn't last long as he strayed a little too far and happened to be face to face with a reporter who had a camera and was a little too close for comfort.
Romeo had never really had interaction with people outside of the mansion, and because he was scared and didn't know what was going on he caused the reporters camera to explode in his face and accidentally killing him, making little Romeo cry and scream from where he was. He alerted his mother who was there in a flash, only to see the damage Romeo had caused and trying to take care of her hysterical son while also trying to clean up the body on her property.
After this incident Romeo didn't go outside as often as he usually did, but still tried to get out sometimes. He loved the fresh air and grass and wind, not the stuffy house, but he was scared, and didn't know how to defend himself. When he got sent off to Hogwarts, he immediately soaked in everything DADA had to offer, excelling in the class even as a first year. Having his brother at Hogwarts was also a help, allowing Romeo to learn some social skills but when he was a 3rd year and Alessio was a 7th year Romeo started to break off from his brother.
Romeo became friends with a Gryffindor boy who was a great help to Romeo in showing him that not everyone was bad and that people could be trusted, and even helped Romeo develop some social skills in the process. Because of Emanuel, Romeo grew to love Hogwarts even more and felt comfortable telling the other what he really was, finding out that Emanuel was half-veela and that made the two even closer.
After graduating Hogwarts top of his class, Romeo didn't return home and moved into an apartment with Emanuel in Lincliff City, the two being young bachelors getting full-time minimum wage jobs to support themselves but living the adult life. Despite also having money from his family name, Romeo did his best to live on his own with his best friend, up until the ministry announced the half-breed decree.
Thankfully for Emanuel and Romeo, the two were able to keep themselves hidden from the decree since neither of them had told anyone about themselves and made sure to keep anything hidden from everyone. It's been a rocky path staying under the radar while also trying to remain as normal citizens, but the two have been doing their best up until this point.