Callum Everett, 16 years old then 32 years old. 

He is one of a set of twins. Himself, Janelle (the main character) and his twin sister Alisa were all incredibly close in high school. You can decide whether Janelle was in a relationship with either him or Alisa. Whichever you choose will not be available in the story as they will have died two weeks before the birth of the main character's children. 

Callum in high school was a sporty, gifted young man. He was an incredibly talented soccer player, but soccer was not something he cherished. If he was given the choice between his soccer or a future with Janelle, he would choose Janelle in a heart beat. He cares incredibly about Alisa and Janelle, and if Janelle chooses Alisa, he is incredibly supportive and even ends up donating his sperm to give them a chance to have kids that have both their genes, despite having feelings for her himself. 

Callum as an adult has become more aloof after the death of his sister. He goes overseas for business a lot, owning his own company which requires him to go to countries all over the world to sell his products. He makes sure to return as often as possible though, not wanting Janelle to be alone for too long. He constantly fusses and worries over her, fearing for her mental health after the loss of Alisa. He adores the twins, but keeps his distance as he doesn't want them to know that he is really their father, wanting to respect Alisa's parental claim. He still has deep feelings for Janelle but will never act upon them, happy to watch over her from a distance. He has no interest in dating other people. 

The voice actor for Callum must be able to do a teenage voice and an adult voice.