
You should space down several lines to keep spoiler hidden. Anyway, spoiler ahead.
Crown prince remembers every timeline. He had his memories from the beginning. So, yes, he remembered his married life with Ines because he also committed suicide in that timeline.
Crown prince knew Ines and Carcel had engaged in sexual activity because when they arrived at the event Ines and Carcel were disheveled and flushed. Kiss/bite marks were also apparent. Neither Ines nor Carcel cared if it was apparent.

Spoiler ahead:
Ines and Carcel marriage relationship is a solid one. No matter what comes their way, they will face it together. There won’t be anything that breaks them up. Even if they fight, they make up right away. So noone and nothing will tear them apart. Most of the problems that they face are from the people from Ines’s past and even those they overcome together.
As to the novel, I bought the Korean novels on Ridibooks.
STOP! PLEASE DO NOT READ THIS IF YOU DO NOT WANT TO BE SPOILED. THIS CONTAIN AN IMPORTANT SPOILER ON CROWN PRINCE.
The truth is, Ines and Carcel are perfectly matched in their sexual performance and enjoyment.
While Ines can indeed be an aggressive and rough woman (she takes after her father in this), she has always acted within normal sexual boundaries in her prior experiences. In the novel she admits the crown prince was a real sexual deviant and there’s nothing she didn’t experience with him. Ines grew to hate encounters with him and as a way to shorten enduring it, she learned how to please him as quickly as possible.The painter was inexperienced and Ines was the one who seduced him so it’s expected that her experience there was within normal bounds especially after she experienced an overdose of the crown prince’s perversion before regressing.
In the novel, Carcel’s performance, on the other hand, had Ines persuading herself early on that she enjoys it only because he’s exceptionally good at it. She told herself any woman would enjoy it so that’s why she enjoys it. The problem is, at some point Ines actually began competing with Carcel. lol Just like she would be upset when after a night of sex he looked refreshed and she was exhausted, she actually began to compete with him and it only took their sex to a higher plane.
Still, after Ines accepted him fully, she became more openly aggressive. There was one point before she accepted him that she felt that she was becoming lewd like him because she felt an “unusual sense” of satisfaction watching him masturbate on her. This would have been back in ep43 but of course they wouldn’t include that in the manhwa. Nevertheless, the more Ines accepts Carcel, the more aggressive and perverted she becomes. She even begins to engage in dirty talk which she used to frown upon when Carcel talked like that early in their marriage. Somehow the more time she spends with Carcel, dirty talk becomes such a part of their sex life that it’s hard to believe that Ines was so rigid and strict in the beginning. They even engage in roleplaying with dirty talk later in their marriage.
So while Carcel is here in this ch talking about another man knowing her true face and how she can be so rough and aggressive, he doesn’t even know it’s him that is bringing out this side of her. This is also evident later in the novel when the crown prince realizes Ines and Carcel had engaged sexually in their carriage. Ines realized the crown prince was irritated because he remembered she refused to engage in that kind of thing with him when they were married in the crown princess timeline. In this instance, it was even Ines who instigated Carcel in the carriage and was completely fine with engaging in sexual activity with him inside their carriage. It shows the contrast with how different she behaves with either man. There’s an even more blatant scene that shows that Ines has completely given herself to Carcel. She even tells him to do “anything” he feels like with her body. It’s probably the hottest scene in the novel’s main story. They were seriously behaving like love-starved animals. lol Even tearing off clothes and not once doing it on the bed. Ines would never tell just anyone to do that. That’s how much she trusts Carcel completely and how much she’s changed from the beginning of their marriage.
So Carcel thought in this ch about her prior experience is pointless. She’s never been like this with anyone else.