Let’s talk about my step-sister

She’s 21, so 10 years younger than me. <br><br>She’s always attractive; but the other day, she made me really horny. I won’t go into details, but it felt like a switch went off and she became sexually attractive to me. <br><br>I’m in a relationship now, and my step-sister is in a long term relationship too. I’m not planning to do anything, but a part of me kind of hopes we both break up and explore this attraction. I’m a little upset that I didn’t feel this way before she was in a relationship. <br><br>Right now, I feel like she wouldn’t be interested anyway and I don’t want to ruin my relationship with her in case I’m right.