I don’t know what to do,

I’m dating a guy out of pity. I know I am awful, but he told me why he loved me and how he’s been rejected three times. I wasn’t thinking straight, so now we are dating. He’s a great friend, and I thought maybe with time I’ll feel the same. I don’t think that’s the case anymore because he’s been pressuring me into: sending nudes, doing sexual favors, etc. I told him I wanted to take things slow we have only been dating for three weeks, but he constantly keeps asking. His excuse is that he’s been wanting me for so long that this is why he is this way. I halfway believe this excuse I know I sound stupid, but he’s cried to me late at night telling me how sad he’s been and how these past weeks he’s been happy. Should I just make up an excuse? I don’t think I have the guts to tell him what I really feel. I am a junior in highschool my parents don’t even let me date. Help.