In the prenatal class (S3:E2)

Great exchange between the teacher and John who's at the class with Kate (why is he even in the class--everything he does is awkward and terrible):

Teacher: Now, dads, during labor, you may find it distressing to see your partner in so much pain. (big smile at John) Is this your first? Not your first?

John (stammering): It's - it's not my first. (a look of fear passes over Kate's face, followed by relief) It's Kate's first.

Teacher: So, you'll know what I'm talking about. It is distressing, but you just being there, gently encouraging her to keep going, that is so important.

John (having navigated the minefield successfully once, feels the need to clarify): It's - it's not actually mine as such. I'm just, uh... Kate's my wife's girlfriend.

The look on the teacher's face as she changes the subject is priceless.