Am totally confused

 I’m really so sad right now, cus I got to know my gf of 2years was cheating on me, This is is how I got to know. I went through her phone secretly and saw her chat with a guy threatening her with her nude video , the guy was saying he wanted to see her, so in the chats, they lodged and had sex. So I sat my gf down and told her not to lie to me that I’ve seen everything, she started weeping and explaining, she said in early 2020 when we started dating, she said she felt insecure about me when she saw me smoking at one occasion, tho my gf was an SU, as a matter of fact, I deflowered her. But note, I’m not a smoker, I just smoke occasionally, anytime I’m with my marlian friends. I don’t smoke when I am alone or with my babe. So she met the guy, she said yes to the guy, they had sex 2 times , so she told me as she saw I’m getting more serious with her cus I took her home, she met my mom, she cook in my mom house, I also went to her house, her mom likes me , she cut it off with the guy, until one day the guy called her and scope her that he misses her with plead, I was in school den, so she went to meet the guy at bar, so she told me the guy got her drunk ,lodge her, fuck her and video her completely naked from head to toe, So he threatened her last month with it and went to meet him, lodge and fuck her again that this is all what happened. Right now I don’t even know what to do if I should break up and chase her away or not and I love this girl 😔