I don't really think I have any good advice, because thank God my parents are together and I've never had to deal with such an issue, and hopefully never will. I know you are scared..........I know I would be too. Maybe you can talk to your mom about your concerns. You never know, they might become your best friends and may not be that bad after all. Remember, no one can replace your father ever. You dad is your dad and will always be your dad. I hope things turn out ok for you! Wishing you the best of luck!