Hello Pampas
I have been to Santorini, though not with JY. It is a fascinating Island, with spectacular scenery courtesy of the prehistoric volcanic eruption which formed the dramatic caldera. The main town is a bit garish and touristy, but there is much to see on the small island, not least the fantastically preserved Bronze Age town of Akrotiri.
In my opinion, It is best to visit Santorini on a holiday which also includes Crete, which is a fabulous island.
I hope you have a lovely time, whatever you choose.
Yvonne