No offense to you Cobra, but the really funny thing that strikes me is how confused you really are. Its like you are trying to talk yourself into whatever appeals to you for that day.
I will lay a million dollars that if she called you up right now and DUMPED YOU...that you would fall to pieces and become the biggest afc in history in trying to get her back. You would go from being obsessed with other women to being obsessed with her. I honestly think you wouldnt know what to do with yourself. The reason why you feel so comfortable trying these tactics on her right now is because you know that she will stick by you while you go through all of this. So in other words, you have hand in the relationship. You feel like she wont dump you no matter what.
Its just how it is when people dont know what they want or have....the grass is always greener on the other side so they say. Until you get to that other side.
I would say your best bet is to step back from all of this for a few days, dont talk to her or anyone. Go with your feelings. If after that time you still have the urge to date others, then by all means do it. IF you are misssing your girl and couldnt stand to be without her another day, then go ahead with the marriage. But I really think the long dissertations you are writing aren't doing you anything except convincing yourself that what you are doing at the time is justified.