I Am a Stepmother

I've never seen a teenager post as often as my SD does about how much she loves her mom. I think love between a mom and daughter is a special thing and it's great she lets her mom know she loves her for all to see but posting it all the time? The reason I'm wondering about this is because she is acting out and while I dont tolerate abusive behavior I would still like to know where it comes from. She lives with her mom and only has visitation with us. I did notice she says she gets in arguments all the time with her mom. Her mom also uses drugs. The only communication my SD's parents have is through legal court orders so I don't know what kind of an attitude her mom shows her daughter about us. Maybe she worries about her mom or maybe her mom is like a child herself? I should probably stop figuring out why and just deal with how it is. Summer break is here so the stress and challenges begin. Last year she tried making me believe the youngest was lost in the river and then tried to make her dad believe i had lost track of the youngest on the river. I don't go to the river with her anymore. I still hope this summer is better.