3 days, where to stay - Flowers and Delft

The lovely historical city of Leiden is an ideal base for both the flower fields and the Keukenhof as well as Delft. And Leiden is a great city in its own right.
You can reach Leiden by train from Paris with just 1 easy change in Rotterdam. And on your way back, you can reach Brussels with 1 easy change in Rotterdam.
From Leiden you can take the direct Keukenhof express bus to The Keukenhof. To get to Delft from Leiden is a quick 20 minute train ride.

Wife wants more of a major city as a base (e.g. She wants to stay at a Marriott)
How is Rotterdam?

Why does your wife want to stay at a Marriott hotel in a major city? I really think that Leiden is an ideal base for you. It isn’t some small village. Leiden is a city with lots of shops, restaurants, museums etc. It’s where the famous painter Rembrandt was born and it has a strong Pilgrim connection. Before you dismiss it, I suggest you at least look into it.

The city of Rotterdam was bombed heavily in the first days of WW2 and its historical city center was almost completely destroyed. The city has of course been rebuilt and although it’s a nice city with lots of restaurants, shops, hotels etc, it lacks the charm of cities like Amsterdam, Haarlem, Leiden, Delft etc.

Driving and parking in Amsterdam or Delft will not be fun at all. It is a quick and easy train ride to Delft, and the Royal Delft factory is a 15-minute walk from there. You mention "Royal Delft." Are you just interested in the factory? Or do you mean all sights in Delft? The other tourist sights in Delft (New Church, Museum Prinsenhof, etc.) are slightly closer in the other direction. Parking near any of these sights will be very problematic.

Tell your wife that Leiden is a MAJOR visitor attraction, with at least 2-3 days of museums and things to do. Okay, it is not a Major City Of The World, like Paris or London. But neither is Rotterdam.

Dutch_traveler’s Leiden suggestion is quite good (as always). It’s a very lovely city with a lot of charm, great public transit connections to the sites you mention and plenty to do in its own right. No need for a car.

However, if you’re exclusively looking for a Marriott property, Den Haag has 3. I haven’t stayed in any of them, but did stay at an IHG hotel not far from the Residence Inn. We enjoyed Den Haag for 5 nights and thought it was a great base for exploring including Delft, Leiden, the Keukenhof, and Rotterdam. I enjoyed Rotterdam as a day trip, but of the cities mentioned, it would be my last choice for a hotel stay.