WordPress is perfect for Photoshop users. There are tons of online help sites and videos for WordPress.

One would need to set up a WordPress site. You could start here for free: https://wordpress.com/

or

purchase an online webhosting solution that includes WordPress in its package (They all do), for about $5-$10 per month. https://www.tomsguide.com/buying-guide/best-web-hosting-services

Plus if you don't like WordPress, these Webhosting services have all the CMS solutions available in their package.

Use photoshop for graphics creation and manipulation.

Adobe XD or Figma for the design, layout so she can export assets at optimal sizes along with some basic HTML and CSS.

Also lets her "demo" the flow and interaction for multi page sites.

She has a website so maybe she already has access to WordPress. For all I know she knows more about what you guys are talking about than I do. I'm just trying to be a helpful husband.

Word of advice, you are only a helpful husband if she asks otherwise it's mansplainin especially if as you suspect she knows more about it than you do.

And I'm coming at it from the other end because my wife is often helpful, or so she thinks.

What’s the opposite of mansplaining? You know, when your wife asks if you know what you’re doing when you’re building an engine, rewiring a house, remodeling a bathroom, etc? :D