Living in sin is not an impediment to marriage? Since when?
I’m willing to be corrected, but I’ve never seen living in sin listed as an impediment to marriage. The impediments I am aware of are the following:
Betrothal
Vow of chastity or Holy Orders
Mixed marriage
Forbidden time (abolished in the 1917 code of canon law)
Impuberty
Impotency
Abduction
Disparity of cult
Crime
Consanguinity
Spiritual relationship
Clandestinely
Defect of intellect