How do I let my bf let me pay for him?

So today I got some big news about something (I'll spare you the details) but my bf invited me for dinner in a very expensive restaurant to celebrate. Now I'm cool with him buying chipotle for me but this is way too expensive. His parents make literally 2% of what mine make. I kinda would wanna pay for him (or at least myself). But he won't let me do that. He says it's demascualting and pathetic for a guy.

What can I do here?