Affectional orientation refers to a person's natural tendency to feel romantic attraction and love towards certain people. It is something that comes naturally to people, just like how you might naturally prefer certain types of food or activities.
Some people are attracted to people of the opposite gender (heterosexual), some to people of the same gender (homosexual), and some to people of multiple genders (bisexual or pansexual). It's important to remember that everyone's affectional orientation is different and it's okay to be attracted to whoever makes you happy.
Just like how we shouldn't judge someone for liking a certain type of food, we shouldn't judge someone for their affectional orientation. Love is love and everyone deserves to be accepted for who they are.