Spoilers!!!
As someone who has read the spoilers(not the novel—big difference, but is it? Idk) I'm not sure if this is true but I digress.
Yes, he truly did love Daphne before and after he knew about the regressions, but after regressing(I'm talking about after he knew of the truth) a lot of times—he started falling out of love for Daphne, and that's where Richard started to seduce the Crown Prince and he slowly fell in love with Richard but couldn't accept that fact, but as we all know; step 1 is denial and step 2 is in daniel(literally with the love potion scene im crine)
And the story goes on but it's pretty much Crown Prince fell first and Crown Prince fell harder(yes CP is both lol).

Did the crown prince love Daphne any of the times that they got married? (Even before he found out she was a regressor? Or has his first love always been Richard?