I don’t know what to do

A boy (15) and I (14) have been talking for about 8 months now. He is so nice to me and treats me amazing. I’m very modest and want to take things slow when it comes to a relationship, but he wants all the sexual stuff. I’m not comfortable with doing anything like that yet ( considering I’m only 14) but he keeps pushing me to do things like send nudes. I keep refusing and he gets upset but hides it and says it’s ok, and he doesn’t want to make me do anything i don’t want. He is very negative about himself and always tells me that he’s a horrible person and I deserve better than him, but I reassure him that he is the only person I want. The other day we got into a bit of a disagreement because I told him that he wasn’t a bad person, he kept telling me that he was a horrible person and I didn’t believe him so he listed off things. He said that “ he would rather have a one night stand than a relationship” and of course that hurt a little, but I asked him if that was directed towards our relationship or just in general, he responded saying just in general but then said “ if another girl tempted me I wouldn’t be able to resist myself” and that was really hard for me to hear. But he said that those were the reasons that I deserved better than him and he would always like me but our relationship was unhealthy for me. I made excuses in my head for him and told myself that he just didn’t want me to get hurt so he just really like me. Then a few days later he said that he was doing a whole bunch of things like he mean to me so I would stop liking him. I’m confused because he acts like he still likes me but does all this stuff to get me to stop liking him. I don’t know what to do because I really really like him. Sorry this was so long! 😬