In the end, Stolas made the decision he thought was the right one. He had already been exposed along with her daughter, and to protect her he would do whatever was necessary. Including consummating his love for her before everyone's eyes.
Octavia would manage to pass off her tricks as one more lie from her mother, thus avoiding being discovered and leaving her mother a liar.
Stella would swear to continue her crusade to destroy the Goetia branch Stolas belongs to. But her life will have very different plans.
Blitzo still couldn't accept that he had lost Stolas, but his pride wouldn't let him grieve or show it to others.
This story is far from over, but at least we can have one thing for sure. The love between a father and his daughter can go as far as it is allowed.