My GF wants a baby but im married good idea?

ive been having an affair for 2 years now because my wife was in a car accident and has real bad back pain sometimes she needs a wheelchair and this has made our life non existent , no amount of pestering or guilt will make her have , so i started an affair with a y co worker who made it obvious she wanted me bad , problem is my gf wants a child and tells me that she loves me all the time ,i tell her i love her too but its only because the is good , she wants me to leave my wife , but i never will because she would divorce me and take have my belongings and the house ,how can i get rid of my gf she keeps saying she will tell my wife, do you think she will tell??is there a female form of viagra i maybe could give to my wife?? very confused and upset about the whole situation