"According to the rules of the Floating Cloud City, unless I divorce you, or if you bring a witness that I am not fit to be husband to the household hall in person to go through various examinations and a bunch of procedures to dissolve the marriage, we will always be husband and wife!" -1468

Yun Che doesn't have a marriage certificate, so his word must be the one that counts in that "I divorce you", and they even had the whole God Realm Powerhouses as witness of that "divorce". He not only verbally said that they were divorcing now, but also left behind a "Blood Mark" to signal the end of their marriage. Unless Mars explained somewhere else how "logically" they are still officially married, they just divorced.

休[xiū] - cast off one's wife and send her home Even if they still have to go through another official process to cancel the marriage, both parties "agreed" on that divorce matter, and Floating Cloud City no longer exist.