When someone is betrayed, they are confused. In Anurag's case, Prerna left him at the mandap without any prior warning and without giving him a proper breakup/closure. This made his initial reaction anger, rather than trying to understand. Now that his initial anger phase has finished, he is able to see more logically and now knows that Prerna had a huge reason behind this wedding and is trying to find that reason.
keya anurag ekbar bhi bola- tum paiso ke liye shadi kia i will never trust this . he literally trusted prerna's speech.. aur jo betray karte toh usko kyu duabra anurag pana chahta hai ? why ? for revenge or ego.. his love is changed in junun . iyea do din ka light moment , chand wale scene , it is their memory revising . but his real intention is to grab mrs prerna bajaj , not his love prerna. he wants to defeat bajaj . that is why prerna said- she is not toy , jisko jab chahe tab le jaye. anurag is not consistent.