Debbie Purdy is concerned her husband could be prosecuted
A woman with multiple sclerosis will hear later whether her High Court challenge to clarify the law on assisted suicide has succeeded.
Debbie Purdy, 45, from Bradford, is considering going to a Swiss clinic to end her life, but fears her husband may be charged on his return to the UK.
She wants a guarantee that her husband, Omar Puente, will not be prosecuted.
But the Director of Public Prosecutions (DPP) said during a hearing earlier this month that would be impossible.
Ms Purdy was diagnosed with primary progressive MS in March 1995. She can no longer walk and is gradually losing strength in her upper body.
She has suggested that at some point she may travel to Switzerland to take a lethal dose of barbiturates prescribed by doctors at Dignitas.
Ms Purdy wants her husband to be at her side when she dies - but fears he may be prosecuted on his return to Britain.
Aiding or abetting a suicide is a crime punishable by up to 14 years imprisonment.
The DPP has not prosecuted any relative of more than 100 UK citizens who have gone abroad to Dignitas to die.
However, the process of how that decision has been reached has never been made clear.
Ms Purdy successfully appealed in June for a judicial review in the High Court on the grounds that the DPP had acted illegally by not providing guidance.
During the hearing earlier this month, she argued the lack of clarification was a breach of her human rights.
But the counsel for the DPP, Sir Ken Macdonald, said the assurance Ms Purdy was seeking could not be given as assisted suicide was illegal.
It is not the first time the issue has been raised in the courts.
In 2001 Diane Pretty, who had motor neurone disease, failed to get immunity from prosecution for her husband if he helped her to die in the UK.
Several attempts to legalise assisted suicide in Britain have also been rejected.
The most recent, in 2006, was defeated in the House of Lords by 148 votes to 100.