hi going in August will limit your options as in many parts of SE Asia are in monsoon season so avoiding Phuket, langkawi and other parts f malaysia would be advisable. That leaves koh samui on Thailand ‘S east coast and Bali. If you haven’t been to Bali I would recommend it. You have many spg options. Would definitely recommend the St. Regis as it is your honeymoon. Not in the best part of Bali to access other areas but great for a few days on the beach. You could do multi locations, perhaps at the soon to be opened Renaissance in ululating and element in Ubud. The W in seminyak is better located but too modern and no feeling of being in Bali Utd just my personal opinion.

re koh samui would recommend the Vana belle or W

assume you would fly into either Singapore or Bangkok so many spg options in each.

there are also a couple of newly opened resorts in da nang ( not sure about weather in this part but think it should be ok)

​​​​​​​hope this helps