Cheated on and don’t know what to do

So yesterday the guy that I have been talking to cheated on me with this girl who I know of but don’t know personally and I was taking to a friend and she had told me what happened and I couldn’t believe it until I saw pictures that were proof and I confronted him and he tried to act dumb and say “what do you mean baby” as if nothing happened snd I repeated “I know what happened last night “ and now he keeps lying and lying and making more lies and we have never said I love you to eachother and then he said it and I dont know what to do or how to feel I just wanna cry and he’s trying to care but idk whats real or fake anymore I don’t want to leave him but I think that he hurt me so much that I can’t think straight so I don’t want to mess anything up and my hearts tearing apart looking at the pictures and videos please give me some advice I feel so hurt