1- Alex Wesker was a researcher working under direct orders of Spencer, and was even in charge oof the project at some point, implying that he knew about Albert. Jake was a mercenary gaining money to sustain his mother, and had no knowledge about his father.I bet Jake is Alex Wesker or another subject from Project W. There is no way that Wesker would have had a child through natural birth . He makes no human connections as they would only stand in his his way in his quest for power and world domination. Plus it would take too long to produce a speicmen. Cloning would be much easier for him to control, he would not have to trust a woman to carry the baby, and would explain how old Jake is. Jake would have to be a result of some experiment.
2- You don't have to make human connection to get sexually involved. Besides that, Wesker wasn't always like that. He only stopped trusting everyone else when he started to question Spencer's plans. And he only became interested in destroying the world when he knew about the Wesker children.
3- Wesker would need a woman to carry the baby if he was a clone.