Look him down and up, slowly and obviously to make him uncomfortable, smile and say, “A high compliment coming from a master of recycling!”
Smile insincerely and say in a condescending manner: “Well, aren’t you the charmer, commenting on another man’s wife’s dress!” Maybe add a “Would you like me to return the favor and ask you how many times you’ve worn your suit?” after that for good measure.
Smile insincerely and say in a dismissive manner: “Why, how stalker-ish of you!” Then turn away and start a pleasant conversation with someone else nearby. Maybe compliment her on her outfit by saying something like: “I have no idea if you’ve worn that dress before, but it’s so very elegant!”
Lots of good suggestions so far. You could also go with a smile and sincere “Thank you!” or , if he asks if it is the same dress, “Yes!” and then look at him confidently. When his put down doesn’t work, he will flounder and be put off and probably won’t know what to say. Another totally different option is to have your husband use the “should I be worried that you remember what my wife wears from year to year?” reply.
This thread reminds me of a time, about five years ago, we were invited to a wedding. The couple getting married worked together at the same business H works.
I didn’t know H’s boss (owner of the business) very well at all. I had met him a handful of times over the years, but never at an occasion where I’d be dressed up. IOW, he had probably only seen me in jeans and a basic shirt. I have super short hair & I probably appear “butch” to him. To get the full picture, his (much younger) wife has a striking resemblance to Mariah Carey. So, lol, there’s quite a contrast.
Anyways, at the wedding, in front of a bunch of people saying hello to each other and doing some introductions, H’s boss said to me, “I didn’t think you even OWNED a dress!”
I was dumb struck. It didn’t sound like a compliment. It wasn’t followed up with how fantastic I looked. I couldn’t believe he said that to me, in front of all those people!
I did have a lot of fun telling friends the story though.
I’m in favor of @conmama saying something upbeat, about how it is her favorite dress & is grateful to have an opportunity to wear it, or using @MaineLonghorn Kate Middleton’s line.
I’d own the fact that you have had the dress for a while…maybe say something like “Thanks for noticing - I work hard to be able to fit into a dress I bought X years ago. And I think it still looks.great, don’t you?”
I’d probably say something about the dress being ONE of H’s favorites and then change the subject. I’d not want to make work awkward for my spouse and his coworkers. There are folks who remember things most of us consider pretty random. Most have the sense not to draw attention to this strange selective memory as it can creep out others. The folks can be perfectly nice but maybe not too good at social cues.
I am sure you and your spouse know you look terrific in your party clothes!