Among the most romantic (and upscale) hotels and lodges in Belize are:
Chan Chich Lodge, Gallon Jug (http://www.chanchich.com) -- wonderful, isolated jungle lodge set right on top of a Maya ruin
Lodge at Chaa Creek, near San Ignacio (http://www.chaacreek.com) -- well-run upscale lodge with beautiful cabanas and lovely grounds
Blancaneaux Lodge, Mountain Pine Ridge (http://www.blancaneaux.com) -- owned by film maker Francis Ford Coppola, Blancaneaux has a romantic setting above a river, with two pools, two restaurants
Hidden Valley Inn, Mountain Pine Ridge (http://www.hiddenvalleyinn.com) -- honeymooners can have their own private waterfall on 7,000 acres
Victoria House, San Pedro (http://www.victoria-house.com) -- lovely, well-run seaside resort, two pools, not too big, not too small, just right
Azul Resort, North Ambergris Caye (http://www.azulbelize.com) -- just two beach houses, but what beach houses these are, with delicious rooftop perches and a pool just for the two houses and a great restaurant, Rojo Lounge
Inn at Robert's Grove, Placencia (http://www.robertsgrove.com) -- well-run beach resort with all the amenities -- three pools, tennis court, roof-top jacuzzis, two restaurants, dive shop, marina, private islands
Turtle Inn, Placencia (http://www.blancaneaux.com) -- another Coppola resort, very exotic with thatched cabanas with furnishings from Bali
Hamanasi, Hopkins (http://www.hamanasi.com) -- honeymooners will like the treehouses
I've personally stayed in all of the above places, most several times, and can recommend them all.
Also with romantic settings and appealing accommodations, are:
Pelican Reef, San Pedro
duPlooy's Lodge, near San Ignacio
Kanantik (all-inclusive), near Hopkins
Five Sisters Lodge, Mountain Pine Ridge
Xanadu, San Pedro
Grand Caribe, North Ambergris
Mystic River Lodge, near San Ignacio
Mata Chica, North Ambergris
Portofino, North Ambergris
That's not a complete list, of course.
May is a pretty good time to come to Belize. Although it's hot (usually the hottest month of the year in Belize), it's before hurricane and tropical storm season, and you get lower off-season rates while everything is still open
--Lan Sluder
http://www.belizefirst.com
Fodor's Belize 2009/Fodor's Belize 2010