A reasonable budget depends on the place. You can get something in the vicinity of what you’re talking about for 2000 to 15000 for two people for the week. You could just ask for money now and wait to go shopping when you have the budget, or you could pull up https://www.kayak.com/packages and spend 5-10 minutes dreaming aka narrowing things down a bit so you can give people an idea. Or you could decide where you want to go and set up the GFM to cover airfare, accommodations, & basic meals, then put a “extras” on the registry—a fancy dinner, snorkel /scuba trip, zip lining, couples massages, guided tour, show, whatever. That fleshes it out a bit and gives people an image of what they’re “buying”, instead of throwing money into a bag.
This gives round trip airfare from lax, which I think is close to you. https://www.kayak.com/explore/LAX-anywhere
Here’s another source for packages with air, hotel, & maybe car. There is a “romantic” category, but idk if that’s your (plural “you”) style. https://www.travelzoo.com/coll.....Collection