I've cheated on every guy I've ever been with, from my first relationship at 13 to now.
I used to try to justify it (they cheated first, I needed money and the side guy was giving it, etc.) But now I've just accepted it.
This guy has a daughter my age and were both committed pretty seriously. Although it hasn't gotten too physical yet, it's so exciting. So much of what I want out of the sex in my relationship that I'll never get.
And in a way, being the mistress adds a new level of excitement as I've never been with a married man. At times I feel so much guilt and anxiety but deep down I've always been a whore.