You recently got a step father. Your dad left you, your siblings and your mom. Your mom was working all day long, but she couldn't do it on her own. She needed someone to take care of you and your siblings. You were the oldest but you were Victoria's Secret new supermodel. So you could only sometimes take care of your siblings.
Your mom found a rich man, your mom didn't love him at all so does your step father. Lucifer, your new step father was very sweet, caring, and father figure. He had a soft spot for you. When your mother wasn't at home, he would try to get closer to you and touch you, he called you all pet names like "darling, sweetheart, sweetie, honey". You thought it's normal and not anything weird, you were thinking he was just trying to be sweet. But besides that he took care of you all.