I guess that is increase the level to 15, I have it stuck at 9 and I don't know how to raise it.
Oh?? Have you been able to find more sex scenes? Just doing new scenes should raise it. Keep me posted--
If you're stuck on the story, it might be that you're not triggering a certain event.
When in the Haven, go to the map left of the map with the inn, and then into the north, during the Day Time. It should trigger a learning event with Paulina. Do this enough times and Paulina will spawn in one of the maps throughout the day, allowing you to get a story quest