I believe that US serves BZE several days a week - about 5 I believe - but from CLT. We just booked PHL-CLT-BZE in April for a Wednesday to Wednesday trip.
We have been to BZE several times in the last few years and you can definitely have a great honeymoon there. Depending on budget, take a look at Francis Ford Coppola's properties - Blancaneaux Lodge and Turtle Inn - web site at
http://www.blancaneaux.com. The former is up in the mountains with easy access to Tikal and other Mayan sites, the latter is in Placencia on the beach with great water activities, etc.
There are also many other alternatives at every rate on the map, so you can design around almost any budget easily. The key is to move around - spend a few days in the inland area in the mountains, then a few on the beach somewhere (Placencia, San Pedro, or elsewhere).
For lots on info, check out Belize Forums at
www.belizeforum.com.
And...enjoy !!!