I have known my husband for 14 years. We have been married for almost 4 years and 4 years living with each other. I met his daughter when she was 3 (now 16). I got along with her for the most part until she turned 12. At age 10 her personality started to change part of it was growing up and becoming a preteen the other part was the changes happening in her life. At age 10 she went from seeing her dad for the weekend to living with him full time and seeing her mom occasionally. She developed a bad attitude with everyone including her father. Whenever I address it he took her side.