HELP ME!!!

Hello..My name is Melissa let me give you a little background info first, I am 20 years old..My boyfriend and I have been together for 2 years. He has a daughter, she is 3. She is not mine. We used to live with his mother and step father. We just moved out and now his ex{the babys} mother is staying there and is there all the time. We brought it to his mothers attention and she just says that I am jeolous and need to get over myself. Now here is the question am I jelous or is this wrong?? I understand that she needs to spend time with the baby but does her mother need to be sleeping there and hanging out there?? My boyfriend and everyone else sees a problem with it but his mother and ex thinks its fine...HELP ME!!!!! I am very upset over this. Any suggestions, comments would be greatly appreciated. Tweet