I just saw this post and put one on the other you posted on ... I agree with you that it isnt a good idea for her son to sleep in the same bed as you both, he is jealous and the situation will escalate ,he needs some help and counseling here and your Gf has to get tough on him Sleeping with family is okay and many families do it usually it stops as the children get older, I dont think it works when the Mom has another partner as all need privacy.You should talk to her ,about the situation she should place consequences on his actions,remove the TV, PC privileges and anything lese he likes , and get him some help .