First story : the omega has been in love with the alpha for a vert long time, and on their last day of college, as he has the opportunity to take him home, he gets to spend a night with him. The morning after, he is too scared of being hurt and instead of confessing he chooses to pass it as a drunken mistake. When he learns that he is pregnant, he chooses to raise the child alone, until he crosses path with the alpha afin.
Second story : The omega is a doctor and the previous omega's best friend. At the wedding of the previous couple, on a island, he meets a (super rich CEO) alpha, and they spend the night together because of a misunderstanding (the alpha thinks he is a prostitute XD). For him it was just a one-night-stand, but the alpha is very interested in him and chases after him. The omega wasn't over his last relationship with a toxic guy, but the alpha is super sweet.
Third story : The omega and the alpha were once childhood friends until the alpha was brought to his father's family (because he is a dominent alpha) and the omega broke his promise to come get him out. They have been estranged since then, but they meet again. The alpha is very cold towards the omega and doesn't to have anything to do with him, but they get in a car accident and he looses all memories after the age of 17 (before they fell apart). To dissimulate his condition to the family (inheritance battle, etc), the alpha's mother makes a deal with the omega : he has to pretend to be his lover (as if their relationship was still intact) and get permanently marked by him in order to stabilise his condition. The alpha overhears the omega talking about leaving once his job is done and getting surgery to remove the marking. The alpha then reveals his full yandere persona : handcuffs, sequestration, etc.
Hyacinth