Are there any good quotes from Romeo and Juliet that speak about the pair not wanting to live without the other?

Yes! In fact, both Romeo and Juliet say out loud a few times each that they'd rather be dead than live without each other. The poor Nurse and Friar Lawrence have to listen to their dramatic claims. Let's see what they say exactly:

1. In Act 3, Scene 2, Juliet tells the Nurse:

"Hath Romeo slain himself? Say thou but 'ay,'

And that bare vowel I shall poison more

Than the death-darting eye of cockatrice.

I am not I if there be such an I,

Or those eyes shut that makes thee answer 'ay.'"

She means, "Is Romeo dead? Okay, if so, then I'll kill myself."

2. A moment later, Juliet adds:

"Vile earth, to earth resign. End motion here,

And thou and Romeo press one heavy bier."

Meaning that if Romeo really is dead, then she'll kill herself, and she and Romeo will be together in one coffin. 

3. And another moment later, Juliet also says this, meaning that she'll let death take her virginity rather than Romeo, since he's banished:

"Come, cords.—Come, Nurse. I’ll to my wedding bed.

And death, not Romeo, take my maidenhead!"

4. Soon afterward, in Act 3, Scene 3, when Romeo finds out that he's been banished from Verona, he says:

"There is no world without Verona walls

But purgatory, torture, hell itself.

Hence 'banishèd' is banished from the world,

And world’s exile is death."

He means that he'd rather be dead than be banished from Verona, where Juliet lives.

5. He goes on to say to the Friar:

"Hadst thou no poison mixed, no sharp-ground knife,

No sudden mean of death, though ne'er so mean,

But 'banishèd' to kill me?—'Banishèd'!"

He means, "Don't you have any way to just kill me instead of sending me away from Juliet?"