I guess this is as good a place as any for a first post.
Love only requires the emotions of one person. But, for that love to create and maintain a relationship, it takes two. All relationships require something from both sides whether it be a business, platonic, physical (FWB), or a commited love.
From what I see, the fact that you mentioned her indiscretion from years past tells me that either you're still a lil miffed from that or that you're trying to to shield your guilt with it. I'm not saying this to offend you. I'm just being honest about what I'm feeling from your explanation and I could be totally wrong. Either way, it leads me to a question:
Did you forgive her? If so then, even legally, it can't be brought up as having relevancy to do with the situation. That's the rip of relationships...we become so wrapped up in the other person that they become the focal point of blame when they screw up when, in reality, we're the ones who could have avoided the drama by seriously asking ourselves if what they did could become habitual or is a sign of a greater problem in the relationship. That's what I'm seing here.
You screwed up...and it seems like you've paid your dues from what you're saying. But, if she's cutting off intimacy and has been for months, then it's time to really ask her if she wants to stay in the relationship. Plain and simple. If she wants out, then move on, bro. It sounds like you're already wanting out anyways. You have to listen to your own instincts...you may find that you want out of this just as much as she does.
Good luck.