Why my girlfriend cheated on me (she told me) and i still love her ?

Firstly., i have been dating this beautiful yound women who is just a year younger (20). We love eachother a lot. Never really fight. This is the second time she tells me she needs time. The first time was the worst because i wanted to die, fight , and just was not thinking. Now this is the second time. And she actually told me she had sex with the guy after her cousin pushed her a little. She left to NC to see her mother and grand mother and some cousins. I did not go because i did not want to bother. However , i was planning to go to france for the summer after her return. She had sex twice with me and in both occacions she was like not into it. So i asked her what was happening and she was hidding from me what really happen. She lied! Then after pushing her a little she expose the truth. :(. I dont know what to do now she still tells me she love me but she cant be in a relationship now ILove her. Only her. She met this guy at the club and never told him she had a boyfriend should i conctact him and let him know that she had a boyfriend she deleted all my pics with her in facebook and added him as a friend After switching her relationship status. What can i do ? I love her so much. Please her me