What Should I Do About My Feelings for Him?

I met a boy two years ago in a mutual professional group. We are both in the same profession, and he is my senior. We started talking to each other, and he developed feelings for me. He confessed his feelings last year, and to this day, he is trying hard to convince me. However, I know we don't have a future together. We are from different backgrounds and different cultures. Our families would never agree, and it would be difficult for me to adjust to his culture. I have tried explaining this to him several times, but he doesn't understand. Initially, I didn't have feelings for him, but now I am developing feelings, which I don't want because we don't have a future together. What should I do? Should I block him and end it all, or should we keep talking to each other, knowing that it will eventually end?