Re: Is this normal???!

What she did with her ex sounds pretty normal given the circumstances.  What you did was downright dishonest.

If her having sex with other men turns you on, tell her.  Don’t just get your rocks off secretly and leave her with a pile of needless guilt.  You should come clean with her so that the two of you have an opportunity to explore this together.  There is a chance to build a very good open relationship in which she is able to have other men in her life and you get the benefits of a sexual woman.