Don't look for or expect a response from W by your actions. This will frustrate the hell out of you. I know it's hard to accept, but this process can take a long time to play out. Your really going to start questioning your reasons for holding out here eventually with the way you are approaching this. Your still so very early in this process and your going to need your emotional strength to battle this.
You have to GAL and stop obsessing over OM. All things are possible in time, but for right now, you have to have the mind set that for all intensive purposes, your M is over. Only when you can achieve this mind set and new lifestyle will reconciliation be possible. Your W can't see you the way you use to be. You have to be as new and interesting to her as the OM is now.
There are no guarantees and there may never be a reconciliation. If that's the case, then your going to have to be in a position to heal from this and move on. DB'ing is not only a tool to help save your marriage, it's something that can save yourself.
18 months is only how long I've been physically separated. I've been emotionally separated from stbx for 2 years. I battled hard and long to save my marriage and family. It took it's toll on me. If it were not for these DB'ing principals, I would have prolonged the agony of this experience for much longer than I did.
Lesson learned.... Save yourself FIRST!
"It is curious that physical courage should be so common in the world and moral courage so rare." -Mark Twain