Dear Monmon,
My family and I have just returned from Phuket last week. We stayed in Laguna region where has 6 super resorts, most of them have private pool villa for up to 6 persons. We (4 persons) stayed in Sheraton Grande Laguna - Island Villa, though no private pool, just a few steps to 323 meters swimming pool. Excellent service! You could book 2 villas to enjoy your holiday.
Tick: http://www.lagunaphuket.com/promotions/last-minute-bookings/index.php for details or contact your travel agents to get a tailor made package for both of you.