11 year old wants sleepovers at her "boyfriends" house?

Hello. I am a single, divorced mom. I have been single and not dating for 7 years. No men are ever brought into my daughter's life but her father.I co-parent with my ex who has part-custody. He pushes our child to have a boyfriend from another area. He pushes phone calls, letters, and sleepovers.We were teen parents. Last weekend, she went over to "boyfriends" and claims they slept in separate rooms. She said she slept in his sisters room, but this is a child who lies constantly and is currently grounded for lying to teachers and hiding homework.I had a long talk with her and she knows all about sex. She has her period and has started asking me when she should start kissing boys. These sleepovers really concern me. My ex will not budge. I have tried. I really have nowhere else to turn and did not know where to post.She sits in her room and writes love letters and poems for hours.I remember my first boyfriend. I was 15 or older. Her letters are quite graphic and speak of how much she loves him and is depressed when she can't see him. Her therapist can not see her for 3 more weeks.So, should I try to contact the other parents? A good lawyer? Has anyone else had a similar situation? Thanks for any help. via /r/Parenting http://ift.tt/2ogD3sX