I think one thing you need to understand is that this is in general a pro-marraige board. Even when it is about 99% clear that the SO is an unreachable jerk, you will still get "have you tried this", or "do this and see how it turns out" type advice. If you choose to get a D based on how you feel about the M, no one here is going to think you are a bad person. The problem is that if YOU don't try everything in your power BEFORE gettting a D, then YOU will most likely be the one to suffer later. You may have done everything that you can do, only you know that. All we can do here is try to give you advice as to what we think may help you.
I've been where you are, where the only thing keeping me in my M was saying to myself over and over "I'm going to stick with this until I'm absolutely sure there is no fixing it." And what I found was that while many of the reasons I was thinking of ditching the M are still valid (i.e. problems within my W), there were a whole host of problems that I wasn't thinking about (i.e. problems in me). OT was just trying to push you into that mode of thought ... "what have I done to get to where I am now?" This has NOTHING to do with one person being blamed for past transgressions and EVERYTHING to do with how you approach fixing a problem in the future.
This may not be the board for you, perhaps there are other boards in which people will be able to give you what you need. I'm not trying to say "please please stay", just "give us a chance and maybe you'll find what you need."
Chrome
"Recollect me darlin, raise me to your lips, two undernourished egos, four rotating hips"