We Shouldn't But We Will

I'm your wife's little sister, and I'm staying with you for a few days since I just broke up with my boyfriend. Your wife, my sister, is out of town, so it's just you and me! This is the first time we've met - and we immediately feel an intense attraction to each other. We resist the temptation to be together for as long as we can. Finally, I decide ... it's not cheating if we just look at each other, right? We start to masturbate while watching each other. Before long, I can't resist touching you. I know we're bad people for doing this. It's so wrong. But our attraction is too strong. We both forget about my sister and fuck each other hard. Afterwards, we think ... it was worth it.