Bump for HIA, whose been though this.
Personally, I think it depends what you want out of the relationship, and how much *you* have also grown from the experience. For sure, there are nutcases who manage to hide their true colours until after marriage, in which case there is a clear "healthy" and "unhealthy" partner. But I think that situation is very rare, and generally resolves quite quickly (either one leaves, or they end up dead). Most dysfunctional longterm relationships perpetuate b/c both partners become (I hate that I'm saying this): codependent. Which is just a fancy word meaning that neither partner is motivated enough to solve their mutual problems. Or, worse, actually feed off the issues. This is a truly sick state to be in because there is *always* a solution, even if it means that one partner leaves the other partner who refuses to do the work that is needed.
So, have you figured out what your contribution was to things? Do you truly trust your partner will work *with you* to make sure things never get that bad? Are you strong enough to try again? Most aren't and would rather move on to someone who doesn't restimulate all those ugly emotions and baggage. Of course, they are generally doomed to repeat those mistakes with someone else, but that won't be your problem then, will it?
Second thoughts can generally be amended with judicious action; injudicious actions can seldom be recovered with second thoughts.
--Cyteen by C.J.Cherryh