She did. He treats all his love interests as possessions he owns. The guy eventually gets a harem (including Hailey and the princess) of women by the time he defeats the Demon King and, although he only marries one of them (Maize) they ALL belong to him, forever. ( ̄へ ̄)
Remember, in the beginning of this manga, she describes this book as a "trashy harem romance novel". As such, he is a trashy cheating sleaze ball.

This is what I dont understand in situations like these... Why cant Maize just point out, or list for that matter, everything this dude has done. Maize met Izu in the first place because of his own actions. HE CHEATED WHILE THEY WERE TOGETHER. Shove that in his face. Make him realize that what and where you both are now is because of him and his decisions. She keeps answering him with shallow comebacks. Just make him realize he was the cause of him losing you. Aghh! So frustrating!