What's an epic Shakespearian quote for the feeling of sorrow left by a recently separated ex-girlfriend/wife?
Give sorrow words. The grief that doth not speak
Whispers the o'erfraught heart and bids it break.
Macbeth, Act 4, Scene 3
Employing another quotation from A Midsummer Night's Dream
Or, if there were a sympathy in choice,
War, death, or sickness did lay siege to it,
Making it momentany as a sound,
Swift as a shadow, short as any dream,
Brief as the lightning in the collied night,
That, in a spleen, unfolds both heaven and earth;
And ere a man hath power to say "Behold!"
The jaws of darkness do devour it up:
So quick bright things come to confusion. (1.1. 141-149)
These lines on the topic of unrequited love, indicate Lysander's perspective that love provides many difficulties. For Lysander, love is a "quick bright thing" brought to confusion by the unchangeable workings of nature and time.
Romeo and Juliet came to mind. Romeo's monologue about how he lost his love, and can never love again, and so on, really tears at the heartstrings. I think this represents how we all feel when we have been dumped.
Well, considering your desire does have something to do with romantic love, I thought I would peruse Romeo and Juliet. First I spent my time on Act V of the play, trying to find something there that would fit, ... but considering how the play ended up, none of the quotes seemed right. However, although I wouldn't call this quote "iconic," I would say that it fits your situation. It explores Romeo's mood as he is pining over Roseline at the beginning of the play:
Romeo: Is the day so young? ... Ay me! sad hours seem long. ...
Benvolio: What sadness lengthens Romeo's hours?
Romeo: Not having that, which, having, makes them short.
Benvolio: In love?
Benvolio: Of love?
Romeo: Out of her favour, where I am in love. (1.1.158-165)
This being said, I truly hope the situation you refer to (i.e. the "recently separated ex-girlfriend/wife) gets a whole lot better soon!
Well, I think you have plenty of material that you could look at for this! Certainly, unrequited love is a central theme of so many of Shakespeare's works, and especially in his comedies. You might like to start off by looking at Helena's lament of how Demetrius, her lover, now despises her and is only interested in Hermia, her friend, in A Midsummer Night's Dream. She says, in Act I scene 1:
How happy some o'er other some can be!
Through Athens I am thought as fair as she.
But what of that? Demetrius thinks not so;
He will not know what all but he do know.
And as he errs, doting on Hermia's eyes,
So I, admiring of his qualities.
Focusing on Helena's character in the play, and how she pursues Demetrius in spite of his lack of love for her might yield other quotes you could use.
You might find it useful to consider Twelfth Night and the way that Viola ironically falls in love with Orsino whilst she is disguised as a boy, and thus cannot declare her love and is left to declare her master's love to Olivia instead. At the end of Act I scene 4, she says:
Yet a barful strife!
Whoe'er I woo, myself would be his wife.
In addition, Olivia, in falling in love with Viola (disguised as a boy), likewise reflects the theme of impossible love. I hope this gives you some ideas!