Mr S,
I echo Shade's comment that you have absolutely nothing to be sorry for.
13 days is a fantastic achievement that will have built resilience. The slip is an opportunity to learn and grow stronger still.
I have been failing for so long, but every time try to diagnose why? Every time, make the plan and your arsenal of tools that little bit more watertight, until one day you reach a critical mass of pieces of the jigsaw that tips you into the victorious zone. So long as you keep trying and trying to build on your progress, you're improving. For example...if you get back on your horse now (as you clearly have just by being here vs falling off and staying off), and you put in another 2 weeks, you'll have edged twice in a month. How does that compare to the old Mr S? Very favourably I would suggest - certainly not failure. All that time back, your improved mood, mindset, perspective about women...they are all victories. Just because a soccer team lets a goal in, it doesn't mean they've lost the game ? they regroup, refocus and push on.
My critical mass of jigsaw pieces came when I joined up here. But by that point I had an awful lot of other tools (or pieces) in place. You have been fortunate to find the benefit of being here as one of the earlier pieces in your journey. The quest is to find the others as you go - and anyone following you can see how many you've collected over the past fortnight. But where are the others? What are the learnings from within, and specifically (as Shade says), where were the triggers - what were the emotional and physical circumstances that led up to the slip. When did it start to go a little off course? Was it a bit of complacency that crept in after your 10 day celebration? Was it the unwanted sext you received the other day that started the sequence of events? Did your routine of coming on here change for any reason and was that a factor? Was the comfy chair just too much of a draw (and if so, why)? Or was it something completely different? Keep asking why? understand, don't judge yourself. The very awareness this process develops will represent further pieces of the jigsaw for you and enable you to see things earlier next time. This is a marathon, not a sprint, and you have made a most excellent start...so smile at the opportunity to learn some more, and look at your slip as a necessary and important step in the process.
?Strength through adversity. The strongest steel is forged by the fires of hell. It is pounded and struck repeatedly before it?s plunged back into the molten fire. The fire gives it power and flexibility, and the blows give it strength. Those two things make the metal pliable and able to withstand every battle it?s called upon to fight.?
I think a lot of us have at least a part of us that we don't feel good about! So no worries man, you're not alone. 
