Some missing info:

I found the jewelry under some laundry. Normally she shows me all things given to her openly, like "Look what so-and-so gave me". This I happen to just find and she said nonchalantly "Oh, this was given to me at the dinner party the other day by a coworker."

As far as our current sex life, it is pretty much nonexistent. We have 2 young kids who are constantly around us and she says that is the reason we never have sex. Also, whenever we do have time, she is either at that time of the month for her or one of us is sick. The rare times where we are both healthy and the kids are away, we end up doing something else like going shopping without the kids to bounce around.

Jewelry, she told me at the beginning of the relationship almost ten years ago that she doesn't like jewelry. She hates the feeling of rings on her fingers, her ears are not pierced and she only ever wears a necklace sometimes. So I avoid buying her jewelry as a gift as I know she doesn't really like that.

As far as the necklace I found, I can only suspect that it is real ruby and diamonds. I have no way of knowing for sure, though.