Consider Anguilla, it has 33 beautiful beaches, and many wonderful restaurants. There is a price point for everyone, including on the beach.
If you are looking for self catering consider Shoal Bay Villas, Carimar or Blue Waters. For a wonderful boutique resort with 19 rooms, take a look at Frangipani, it is on a great stretch of beach, wonderful hands on owners, many amenities including a gym and spa, water sports, managers cocktail party and boat trips. It would be my pick, casual pampering and a perfect memory for your 35th.