Cheat again, yes. He will throw a birthday party for Ariadne and since Isabella was so jealous, she snuck into Ariadne's room and found Alfonso's love letters. She then shows them to Cesare and he's so sad he starts to drink until he's drunk and Isabella sleeps with him. But after that he starts to ignore Isabella again so during Ariadne's party, she tries to seduce him again on a balcony, her friend Leticia luring people in to watch so that it creates a scandal and Cesare would be forced to marry her to protect her virtue. But her plan backfires since Cesare refuses to marry her, even though Ariadne has broken their engagement because of adultery, and her father is so furious that he sends Isabella to a covent.
Also, I felt like none of the princes are on the level of our Ari!! She is such a strong matriarch type character that the princes' roles fade in front of her.
Somewhat felt that the white hair Raphael suits her, since he is emotionally and mentally a huge support to our gal Ari! He could provide her a calm N nurturing relationship. He didn't want to be an heir to his own family so I believe he could marry Ari and support her to become head of her family (cuz that head position is what she truly desires since the beginning!)
But idk, the spoilers say Alfonso is the ML- so I hope he returns as a strong enough character to equal our Ari's charisma.

Spoiler
I think this is the point where the king will announce that he will remarry and take Ariadne as his wife. Truly a sick a**hole