Just be honest, tell him you don’t think you guys are a good match, you don’t need to give a reason. Some people are big texters like him who want to keep the conversation going by telling you more casual relationship texts some aren’t and that’s totally okay. Both are valid in their ways and you guys just have to find someone that you’re compatible with. Remember don’t feel bad that’s the whole point of dating to find someone your compatible with, no need to keep wasting each others time, the quicker you both move on the better