Hua Hin is a small beach city close to Bangkok. Its not the most beautiful beach in Thailand, but its very close to Bangkok (I got there in about three hours from Victory Monument using the mini van) and its a lot nicer than other destinations close to the city such as Pattaya and Bang Saen, both of which have dirty water and too much nightlife for a relaxing weekend trip.
One of the best features of Hua Hin is the amazing range of great hotels there. I stayed in the Centara Grand Hua Hin, which is one of Thailands oldest hotels. It was built in the 1920s and has the most amazing facilities of any hotel Ive ever stayed in. Its very hard to find old hotels in Thailand as most buildings arent constructed to last a long time, which makes a place like this very special indeed.
There are other good options in and around Hua Hin, besides the Centara Grand. The Hilton is right on the beach and also has good facilities, although its a newish building (I think from the 1990s) and isnt quite as nice. The Intercontinental, which is only a few years old, is also nice and backs right onto the main Hua Hin Beach.
I try to visit Hua Hin at least once every 2-3 months when Im in Bangkok, because its the best beach resort close to the city and its very easy to access. If you want a relaxing place to spend the weekend with your partner, give it a try!