You could sense that things were starting to become serious between your wife and her boyfriend, but she has never told you who he is and he's never come to your house before while you were there -- until today. As you hear the doorbell ring, your heart skips a beat, and then you head down to greet him.
Of course, you know that you don't REALLY have a choice, because you know that this is what your wife wants, and when she wants something, she always gets it. And right now, what she wants is to make you her cuckold.