Ye Linghan forcefully turned Ji Ran from an Alpha to an Omega.Ye Linghan divorced Ran because he thought he didnt change, Linghan still kept Ji Ran in his house, in hopes that the omgea instincts would kick in

You aka Ran was about to tell Linghan that he had successfully changed...but then he saw a news article stating that Linghan was engaged to someone .... he felt betrayed and heartbroken.... it was an eye opener to just how toxic Linghan was. Linghan didn't know Ran converted (BL!)