whatever you think dont lead her on or suddently get cold feet shes on her own and has probably been relying on you for love and support.
The new baby will only know you when its born-do you want to be its stepfather? I will tell you the baby will bond with you although!
How would you feel if the father suddenly decided he wanted contact with his child? You need to discuss this with your gf-is the 8 year olds dad the same as the baby's?
Are u absolutley sure this woman defiantely wants to be with you and genuinley loves you and she is not just with you because she feels vulnerable/ alone/ insecure considering her position and the trauma of what her husband did? she could feel very different in 1 years time uve only been together a hot minute. Take a step back, evaluate the situation and si down talk to her. Remember her son has just lost his father/stepfather whoever he was to him. Im not trying to put doubts in you im sure you do love each other but go in eyes open.