Skimming through, a couple of comments;

1: It seems that your main issue is that you wanted privacy and she either didn't understand or was uninterested in respecting that. Not everyone is 'in the closet' and those who aren't in the closet generally have a hard time dealing with privacy desires of those who are.

2: Spending time with someone who proposed having sex with you isn't cheating in and of itself. If it was, I would have an extremely hard time keeping female friends (~80% have proposed at one time or another and I'm no sex magnet, regardless of what the rumors say).

3: I see signs of some serious cling/desperation. You mention the years it had been for you and how long you tolerated this. This leads me to suspect that you were very heavily invested in making this work, even against signs that it wasn't going to. It's fine to be hungry, but don't let starvation lead you to trying to make a meal out of poisoned fruit.

So, a reason to be upset? Sure. If she wasn't willing/able to respect your privacy (and you made it clear to what degree that was expected) then she should have said so. However, as soon as it was clear that she wasn't going to do so, you should have said your goodbyes, rather than stick around and suffer hoping she would change.