Their names may be bywords for passionate love, but perhaps Baz Luhrmann was more on the money when he summed up Shakespeare's Romeo and Juliet as 'two young kids who have sex and commit suicide'. Is the fire of their love a passing illusion, made so intense only because it is so short-lived? What would happen if they didn't in fact die but went on to live into their 40s and have a daughter?

This question is the springboard for Lost Dog's latest dance theatre piece, written and directed by Ben Duke and performed by Duke and Soléne Weinachter. Juliet and Romeo dodged their fateful ending and ended up in Paris. Now parents to young Sophie, they've tried everything from couples massage to hypnotherapy to heal the wounds of their relationship, and have resorted to acting out their memories in front of an audience, to see if they can reconnect with their romantic selves. 'It won't work without an audience,' Juliet tells us (presumably because that's what characters in a play need in order to come to life).

This wry nod to artifice gives a flavour of the piece's tone, but though its concept is playful, at heart it's full of sharp perceptions into love and marriage – and sometimes pierces so deeply you don't know whether to gasp, laugh or break down in weeping recognition.

Juliet has grand delusions about their romantic past (or perhaps has implicitly acknowledged the lies we tell in order to maintain romance). Her version of their first meeting is shot with quiet erotic power, while Romeo's is a jamboree of swaggering lust. Later it is Juliet who forces them to act out their death scene again and again, clinging onto it as the apotheosis of their love, a substitute for sex which Romeo continually attempts to wriggle out of.

Duke excels in knowing when to pick up movement when words will no longer do, and his work never feels like a mixture of dance and theatre but rather like a story that can be told no other way.

On arrival in their new Paris flat (realising they are on the cliff edge of the rest of their lives) the pair enact a pas de deux that is a sublime tangle of jumbling limbs, half-climbs and clumsy clings; a middle finger up to the sugared romanticism of classical duets. Following a miscarriage they come tentatively into harmony in a healing partner dance – it is telling, perhaps that this tragedy brings them closer than at any other point in the piece.

Though the script doesn't stray far from the conventional trials of relationships, it somehow manages to make familiar clichés feel brutal by saying the unsayable. Juliet fantasises about murdering her baby and wonders how much sleep she would be able to grab before the police arrived. Romeo admits he sometimes sits outside for twenty minutes just to forget she and Sophie exist.

Eventually, it seems they are hurtling towards destruction anyway – not through the stars but through their obstinate attachment to the idea of perfect love, a ruse of nostalgia and half-true memories.

It could be a damning indictment on the whole idea of lasting love, or it could be a reassurance to us mortals that just as that the brightest stars burn the fastest, so the most intense loves cannot sustain themselves unless they are willing to grow.

Dance Base, until 25 Aug, times vary, £13 (£11).