Sis porn hard choice: Stepsister's trust or taboo sex?

My stepsister and I are very close, although we are only stepsiblings; she treated me like a real older step brother, because I always tried to help with her problems. However, this day revealed our true feelings for each other! I just sat on the couch and scrolled through the Instagram feed, as my stepsister disturbed my loneliness. She was very upset and talked about her problem with a guy. From her story, I immediately realized that he behaves like an asshole, but deciding not to upset her even more, I said that it's better not to take such decisions in a hurry. The same day in the evening, stepsis found me in my room. She came in tears and reported that her boyfriend had cheated on her. I felt terribly sorry because she is a beautiful girl, and would be a gift to any man! I tried to reassure her, hugging a little, and immediately felt my pecker showed some interest. My stepsister also noticed this, and with surprise on her face, took it out of my pants.