Is the questioner sinful for lying by claiming marriage in order to sever a forbidden relationship, given her categorical refusal to return to it?

Praise be to Allah, who has blessed you with repentance from the forbidden relationship. You must remain steadfast in your repentance and uprightness. Know that there is no sin in lying if it is essential for a praiseworthy purpose. It becomes permissible if the goal can be achieved through it without speaking the truth, and obligatory if the intended purpose is obligatory. Sincere repentance necessitates avoiding the causes of sin and cutting off the paths that lead to it.