If after 12 years of marriage I can not say I would do it all over again, can our marriage ever work?

There have been so many struggles, so much heartache. Sure, there have been good time but they seem to be overshadowed by the bad. We are separated, but trying to work things out, and he has just hurt me again. I want to work things out but I just don't know if I am fooling myself. I can't say whether I would do it all over again or not. I find myself wondering what life would have been like had I dated more and married someone else.