You do not get a choicw in wheter your husband has an affair. You do get a choice of whether that behavior will be tolersted by you. So what is tour response.
I will not be friends with anyone who is willing to lie to me.
I will not engage in any physical relationship with anyone who is willing to bwtray our solidarity.
I will not x while domeone does y...it is to protect youraelf from harm.
Bounce some here and you can work through this. Just remeber, whike he is involved with someone else, you cannot work on your marriafe. You cannot force hime to do anything, like break up with a girlfriend...You CAN work on you and really start to move forward in your life....does that make sense?