It is better that you find out now before too much time has gone by. It is a blessing that you don't have any kidds together and that you are getting out of this relationship. It seems that he was never really honest with you from the beginning and it will probably never change. Stay strong and know that we learn from our mistakes, and what doesn't kill us, makes us stronger.
Good luck to you, and remember you deserve better.
I also want to tell you that I was in a very similar situation a few months ago. I did not leave my husband for several reasons but mostly for my children(2). I am so glad that you don't have children and can easily cut ties with that dirty pig!
You should kick me out and get a roommate. You are just making yourself miserable living with him. I did not have any family and few friends but I made some. Take care of yourself....