Having trouble finding menswear color.

For colored suits I always recommend ASOS first. They have many options, for example:
https://www.asos.com/us/asos-design/asos-design-wedding-super-skinny-suit-with-micro-texture-in-mid-blue/grp/30601?colourwayid=16623165&cid=5678#14526061


My fiancé is wearing dusty blue and he got his suit from Banana Republic, but that particular one isn't on sale anymore.
Other random ones I've found:
https://suitshop.com/products/light-blue-jacket/

https://www.tedbaker.com/us/Mens/Clothing/Suits/ANECJS-Slim-Fit-Sharkskin-Suit-Jacket-Light-Blue/p/256471-LT-BLUE

https://www.macys.com/shop/product/bar-iii-mens-slim-fit-linen-suit-separates-created-for-macys?ID=6126628&CategoryID=17788&swatchColor=Blue

There are a lot of options. It depends on their budgets too.

Have you tried taking a look at Etsy? We wanted an emerald tweed suit for my FH & found a beautiful one that fit perfectly on there!

Friar Tux has a nice light blue suit you should look at as well:

https://www.friartux.com/rent/suits-and-tuxedos/suits/light-blue-notch-lapel-suit

When is your wedding. Those are mainly spring colors. You may want to try Amazon, I know that sounds crazy, but my friend found similar colors there last year. Or reach out to a local men's suit/tux store in your area, they may be able to point you in the right direction.

Mensusa.com