DP's birthday is soon. There's a new restaurant in town and it's his favourite type of food so I suggested we go there. I follow them on FB and noticed after he had agreed to go there but before I booked that they're offering a particular main course for free if you used the link to book. It just so happens that it's what I would order (DP wouldn't, not spicy enough!). So, that's it really, and my question is whether I should mention to him that my main course will be free. I don't really want to, but then again I'd be so embarrassed when the bill comes if they say "Oh and your "noodles" are on the house". What do you think? (I'm paying of course! and we'll be having drinks and starters too)