Does Clarisse live in Percy Jackson?

Answer 1

The books don't say. They don't say what happens to them though i expect they do marry. Maybe the answer will be in the new series, Heroes of Olympus

Answer 2

She starts dating Chris but there is no record of a marriage.

Answer 3

So far, yes. Silena Bouregaurd took her Armour and pretended to be her, which led to Silena's death(in the Last Olympian, by Rick Riordan). But Clarrisse survived.