Oh, I'm sure she noticed you de-friended her on FB. FB often times is bad news. You did it for the right reasons. You removed the temptation to see what was going with her. Besides, it creates a little mystery, too, because she can't look at what you're up to.
I just don't get on to FB anymore. If I do, it's just for a few minutes. I purposely don't look at anything of my W's right now on FB.