Plz help me anyone plz asolve this problem of mine?

i was in luv with a girl. We were in distance relationship. We both r committed. Even we want to marry. We used to talk daily. she was the motivation for me. she met a guy in her life there. she bacame close to him she talk to him roam with him. and at night she talked to me. i want to have her time to b focussed in studies but she frequenly roam with him. i didnt like tht sometimes i restricted her but then she hardly listen to me. One day i came to her n saw her mobile n get to know tht she shared a kiss with him. i rebuked her badly but pardoned her. then i restrictd her tht she rarely talk to tht guy. after a month she told me that she smooched him and she felt tht guy touching her feeling her smooching her daily even in those days wen i used to call her n care for her. She didnt had except she had everything. Just tell me shud i pardoned the girl . And even that guy too ask for forgiveness, and asking pardoned me too but he didnt told me anyting.he said dont snatch her frm me as i restricted her to restrain all realtion with him. wht sud i do