Unhealthy Sexual Relationship - my 14 year old step daughter

I am the step mother of a 14 year old girl named X. My husband and I have both his daughters living with us full time and they have access visits with their mother on alternate weekends and some holidays. She started 'seeing' a boy online last year through facebook, he is 17. After finally meeting in person they started 'going out', after a few week he 'dumped her'. She had been to his place supposedly under parental supervision and he had visited at our place under heavy supervision. After she was 'dumped' we discovered that her younger sister (13) had been sending him nude pictures of herself, he was very active online with the sister for a while until we discovered this and put a stop to the contact. After a few months apart the 17 year old was back talking to X online and promising her that he would go out with her 'maybe' just did not want to commit. X is under the care of a psychologist when she is with us as she is morbid, unmotivated, argumentative and cutting herself. We have limited facebook etc to only certain times and get no support from her mother who acts as her best friend. We found out that X had had a sexual relationship with the boyfriend whilst supposedly under supervision at his parents house when they were going out the first time, after which he 'dumped' her. We do not like this boy at all and now X is using her mother to see the boyfriend. X's mother agreed to have him stay at her house during the 2nd half of the xmas holidays (3 weeks) during this time he asked her to go out with him again, and the mother gave them their own bedroom !!!! This we only discovered 3 days ago. The boyfriend 'dumped' her again on return to school stating he was too busy for her. X has recently come down with Glandular fever with complications of Hepatitis.The incubation period puts the contraction of this whilst at her mothers. We have also discovered that during this stay X was giving her boyfriend oral sex and he bled profusely into her mouth. We have had blood tests done for her in regards to HIV etc and are trying to cover all bases for X. We have banned her from seeing this boy and said we will not support anything to do with him. X's mother is continuing to support the relationship and this woman has told both her daughters, who have both now lost their virginity whilst in her care, that it is ok to have sex with someone if you like them !!!! We have rung the boy's parents and they are not supportive but said they can't do anything. I am wondering how we should approach this? What are our legal standings? Any advice from anyone?? Pease help us :( We feel like we are living in a nightmare.  

[AnnieBrooke]

It seems as though the judge who granted the girls visitation with her mother should be acquainted with what is going on and asked to remove the girls from their mother's care.

[stepmumburnout]

That is part of our problem at the moment, there are no orders in place, the girls want to live with us but just visit the mum, by the time this got through the family law courts it would be another 12 months down the track :(

[AnnieBrooke]

If there are no orders in place, then in your husband's shoes I would not let the girls go back to the mother's.  

[stepmumburnout]

Trying not too, but it is hard to control teenage girls, the mother collects them when we are not there, keeps them extra nights so they miss school and then when we say "well you look after them then and deal with the consequences" she sends them back as she does not want to spend her money on them. We are nearly at our witts end, we send them to private school, they get psych counselling, the whole thing costs us a fortune, we can't afford a solicitor to go to court and have been advised by a family law solicitor that no court will stop visitation anyway, the system is ridiculous. I have no idea what the police think of this and do not want to take that step at the moment but I honestly think they won't care anyway....