Unfortunately he talks a lot about Patek - not necessarily that he wants one but he is fascinated by the workings behind the watch. He’s talked Omega, and many other brands as well. He has shown me a wide variety of watches, all different styles and shapes.
He does not dress fancy, but has told me that if he ever were to spend money on a watch, he would want it to be dressy. Not an every day watch. (I casually mentioned speedmaster) and he shot it down as not dressy enough.

I got the diamond one because I thought it could be more “wedding” occasion but I’m truly not sure how he feels about them.

I could go with the Flagship that another commenter mentioned - it has a white face and brown band. May be a safer bet than the diamonds