Guard your heart. I would really hate for you to open back up to him only to have him walk out and crush you all over again. I have a friend who has been divorced for a few years and out of the blue her X texted her telling her he broke up with his GF and wanted to get back together. In her case it was a no-brainer to ignore him because he physically and emotionally abused her and had continued the emotional abuse even after the D. Two days later she found out he was back with the GF.
I'm not saying not to give it a try, but be very, very careful not to open yourself up to being hurt again. I'd keep that wall up until you see real signs that he's serious about this, and then only take it down a brick at a time.
