Which is the best Romantic place for a second honeymoon---St.Lucia, Anguilla or Turks & Caicos?

For me it depends more on the resort than the island. You can find romantic resorts on each of those islands which should provide a very memorable vacation.
Turks and Anguilla are not pretty islands. They have very little vegetation or terrain.
St. Lucia is just the opposite.

For peace & quiet and beautiful beaches...where you can find a place for the 2 of you, I would suggest T&C. They also have great restaurants for some romantic meals.
Me and my boyfriend went in May - it was by far the most romantic trip we had together. I think for the fact that we have been on cruises and more up-beat islands - that this was the complete opposite, which is what made it absolutely wonderful!

We just returned from our second honeymoon in Turks & Caicos on 8/10. We spent two weeks there. We also considered the other islands but had concerns with safety. After researching the islands, we found that Turks had a reputation of being safer than most. It's true what they say about the vegetation and terrain, but the water is absolutely beautiful...white sand, turquoise water...it's like being in a pool. It's a very quiet island and there is very little to do. It was very romantic for us...it's what you make of it. Also, the food is very expensive but delicious. We really had no complaints about the restaurants.
Good luck!

Croix, for intimacy Anguilla is great. And the resort I like to recommend to you is http://www.anguillagreathouse.com/

Regards,
Tabitha