So there was another lifetime where they were married but Inés doesn't remember that one?

Yes, if you read some spoilers here at the comment section. In their first life, Ines and Carcel were married. Had the same house and people. Ines can’t remember it because she died due to sickness. (She only remembered her 2nd and 3rd life because that is her punishment for unaliving herself)

Girlie living her 4th life then??! Shit's tough