Help with Bible Study

As you all probably know I help teach a Bible Study to 8th-10th grade girls. We mainly talk about girl problems, dating problems, etc. So, last week they saw me talking to a man at a dinner/dance at our church. Some of them said, "who was that? You need to go out with him." And I said, "well, he is married." And they said, "So." And I said, "What? I know his wife and he is married. You don't do that!" And one said, "have you seen Sleepless in Seattle? She was engaged and went after Tom Hanks...." I said, "Well, you all better get ready because our next lesson is on infidelity."

So, next week is fast approaching and I am in charge of the lesson. I am open to suggestions on good ways to tackle this issue. I thought it would be interesting to see what you all had in mind. Let me know your stories, thoughts, book suggestions, Bible story suggestions. I am open to whatever.