"Change Partners" by Araucaria

LORENZO and JESSICA, BENEDICK and BEATRICE, and PETRUCHIO and KATHARINA are clearly well matched in a way that (amongst almost all the others) ANTONY and CLEOPATRA, and DEMETRIUS and HELENA, are not: this could be corrected by a swap - ANTONY and HELENA, DEMETRIUS and CLEOPATRA. Each of ten across clues is a partial clue to two such new partners run together: one of the two (you have to guess which) is to be inserted in the diagram.