Content generation SaaS. One of the first customers is asking for exclusive access for 2k/month. What do I do?

A few weeks ago, I launched AI-powered content generation platform (specialized in producing highly referenced blog posts). The app is still in early stages of development, but I've asked for a few people feedback, and one of the agency owners really likes it. He offered to pay me 2k/month for access to a few customizations, but he wants them to be exclusive to them. While it's tempting, I also see these features as valuable additions for the app's future. What should I decide?