Screen door locked, purse in house, sleeping in same bed. I don't care what either of them say. He f*cked her. I'm sorry you had to go through this. Frankly, if that was me, I would have attacked both of them. Not only would I be pissed over the cheating, but also over the fact that he put your health at risk. Get tested for STDs ASAP..
If your wife gets help and starts to come around, would you still be interested in the women from work? If not I say don't pursue this at all! Don't get her hopes up of starting a new romance and then down the line you tell her "Thanx, our little fling was great but I won't be needing your serves anymore, my wife is back." I know thats not what you would say but thats what she will hear..