3 adjectives to describe inconstancy

Shortly after their return with the Stuart dynasty, the illustrious Count de Grammont, exiled from France in 1662, won the affections of Elizabeth, Antony's sister, and then with characteristic inconstancy, chose to forget her; but he was caught up at Dover by the brothers Antony and George, and brought back to fulfil his engagement.

Of constant changes I never heard, except in one of Congreve's plays, in which the fair sex is accused of constant inconstancy; but suppose that for constant you read frequent.

Many accidents therefore may happen, by which the ardour of kindness will be abated, without criminal baseness or contemptible inconstancy on either part.

3 adjectives to describe  inconstancy