Is booking activities essential for a honeymoon?

Hi everyone. I'm planning a surprise honeymoon in Fiji for my fiancee.

We're going to be in Shangri-la Resort for a week.

My question is, are honeymoons by 'default', expected to be full of paid activities, like snorkeling or scuba diving or cruising, etc?

I'm planning to book this good package at Shangri-la, and the room is basically in front of the beach.

If I don't book any extra activities, is it still an acceptable honeymoon? Or will we be bored after going to the beach, swimming and lounging around?

Can the activities be booked once we're already at the resort, or are those really booked out months in advanced?

First time doing all of this, so I would appreciate some help.