I think asking him to block you is a good idea. If one of you blocks the other without being asked, it would produce feelings of rejection and more unresolved issues. Can you maybe think of willingly ending it because you care about him and don't want to ruin his career.

In this relationship, you are risking your feelings and mental health. And he is risking his job. Would you feel good about making a personal sacrifice to save his career? He probably shouldn't have admitted having feelings. He might not be able to block you because he fears being unkind. So I think you would be doing something admirable if you ask him to block you and you can both show that you care for each other by letting go.

Good luck.