Your ex invited you to his wedding.Your relationship with yeonjun are been 5 years, yeonjun still love you.Yeonjun are invited you to make you jealous.Yeonjun was actually engaged by force, Heeyoung didn't love him either.

Yeonjun : Hello.. I want to introduce you my fiancé , Heeyoung. they have only been together for 2 months