Hi, i have stayed at Riu hotels in Dominican, i presume the dress code will be the same. In the evening in main restaurants it was no sports clothes - ie no football shirts or shorts, no vests or beach footwear (flipflops). Smart shorts, t shirts etc were fine. For the ladies it was no bikini's at anytime. In the snack bar anything goes, shorts, bikini's etc. Your husband will be fine in jeans and polo shirts. Hope this helps. You will have a fabulous time at Riu, the staff are so helpful and the food is excellent.

thanks gilly