Why do our teenage daughter's get embarrassed when their mum and I talk about our how great our sex life is?

Why should our daughter's get embarrassed when we talk about our sex life? I mean just because their mum and I like to go at it like rabbits, why should it bother them? They have now asked for ear plugs before they go to bed, because they say the commotion coming from our bedroom every night is keeping them up.