If you're reminiscing about a relationship you had 9yrs. ago, then it seems there are other issues at play. I wouldn't want to to start over with an ex. They're an ex for a good reason.
I also think if you're miserable, don't stay together but you have to truly know. I've seen the effects of long loveless marriages caused by social pressures. Using the excuse of staying together for the kids can be damaging to your kids later on.