[Confused In PA]

so after some time to deal with this mess, I've asked her the obvious question, Why? Her reply was "I don't know, it was just sex" and "it didn't mean anything"

I don't know what others might think but I don't buy this. There is/was a reason, there's always a reason and YES it did "mean something" to me.

So as not to aggravate an already tense situation I've asked her to write me an apology letter and "try" to explain what would possibly make her think that this would be o.k. I'm not expecting anything more than what I've already heard but who knows. I'm still baffled how someone who is otherwise very responsible would meet with a complete stranger whom WE only met once.
To me that is just plain stupid.

One other note, I created a single profile on Swing Lifestyle just to see if the guy was still around and his profile was set to "invisibile" 133 days ago. Now I'm wondering if it really was a one time thing. There are too many things that don't make sense to me.

Lastly, I mentioned that I should have taken to heart things I read about single males. I do not blame him, I blame HER. I also blame myself and can't help but think we should have looked for another couple. Then maybe, not a guarantee, but maybe this could have been avoided.