What should I do about this situation?

I’m 33 my ex is 44 he likes someone who is 24. I dated my ex when we were working in the same department. When the 24 year old came along he kept flirting with her it was obvious he has feelings for her I deleted him on Facebook. He kept asking me why do we always get defriended on Facebook. I deleted him because I kept wanting him back. My question to you is should I block him? The reason we broke up is a long story why was he asking why I don’t have him on Facebook if his feelings for the 24 year old are obvious. When we were in the same department he ignored me and paid attention to the younger women. I sometimes have mixed feelings about blocking him. Lesson learned not to date a co worker in the future.