Phuket, Bali, Lankawi.....all are truly amazing romantic getaways and I am jealous as well. The last time we traveled without kids was our honeymoon and the only thing I remember about that is walking (or rather running) behind hub through streets of KL and throwing up after a "thrilling romantic ride" in Genting

(He actually thought that hiking a city and going up to sky and a free fall down is romantic

)
Learnt a valuable lesson....Never let your man decide on such important events in life. Good that you are the one planning this. Have fun!