Did he break up with you 2 years ago, you with him, or was it mutual?

I think you should just maybe give it some time and see if your head clears. Keep getting to know the guy you’ve been seeing since that could potentially go somewhere or develop into something, and if that isn’t an exclusive relationship and you are still wondering if you should give your ex another chance, I don’t think it would hurt to get to know him on a friend level, just to see if he has grown and changed in a similar way that you have or you may not even be compatible now. I’d think your decision would become more clear over some time.