On some level I can understand what happened to her. If I offered a male friend a comfort hug because he recently had a break up but he misinterpreted it and ambushed me with a kiss, how would that be cheating on my part? Since you had her permission I think you were fine in sending that text..
You can say 'til you're blue in the face that you don't want to date, but if your actions include asking out a girl, taking her out and trying to sleep with her, some of them will still be hurt..
Don't take this the wrong way..
I sat reasonably close to her and we had a few brief intermittent comments, while I watched TV and she texted away. Eventually I said something and she couldn't hear, so I sat right up next to her and we started chatting. We actually had a very fun conversation, bought her a glass of wine (only one) then her roomate (she explained a related story) a very called her (lasted nearly 20 minutes lol) but she would look at me roll her eyes, or hit my shoulder if, I guess, something was funny..
Did somebody flick my POPULAR switch when I was'nt looking? What the hell is going on here!?.
That's clearely a keep!.
Tell her you can be friends only, and say hello here and there, but nothing more..