Getting Back w/ Your Ex after Years of being apart

Ok so, my ex and I broke up years ago (2011) he talked about marriage and he took me to jewelry stores to see my taste in rings.  I just KNEW he was going to be my husband.  Nevertheless, we took a break (under my suggestion) and that break turned into the demise of our relationship.   He married a girl in 2014 and got a divorce a year and a half later.  He and I got together this year and it's like we never were apart.  Am I wrong, silly or naive for giving him my time?  Also, do you think that it is ok to give your ex another chance?