I love it as is! I’m especially impressed that it’s your first project of this type, you should be proud of the product and I am sure your hubby will love it too. Thank you for reminding me that I also need to finish up my own Valentine’s Day projects haha.
If you’re looking for a pop of color, two possibilities came to mind. An epoxy fill could look quite nice. A thin stroke around the people to support a separate color fill would help them stand out. Then again, might not be the best option on a 1-day deadline. 
The other possibility I thought of is to cut it again with a different material, and use the material you removed as an inlay. If the material is dissimilar and you want a flush fit, be mindful of the kerf. This tutorial/tool should make it a breeze.