Since my ex re-added me on social media he saw my story once but then hasn't said anything to me nor has he posted anything. Why? What should I do?

We had dated for 2 months then our relationship had been on and off for another 2 months, before he broke up with me and blocked me on FB 5 months later. I heard he was seeing other girls and once publicized his new girlfriend on social media after blocking me for about 2 months. I remained in no contact with him even then but he unblocked a month after that. It's been another 3 months since then and he sent me a friend request last week..
Since my ex re-added me on social media he saw my story once but then hasn't said anything to me nor has he posted anything. Why? What should I do?
Post Opinion