URGENT - domestic violence

I got called to the police station, when I arrived very worried the police officer asked me to confirm my partners details when I done this she explained 'Claire's law' which is all to do with domestic violence, she went on to say that in 2004 my partners ex had logged a domestic violence incident which he wasn't charged with and then early this year he was arrested and charged with domestic violence on the same girl but when it went to court he got found not guilty, so basically because I have a 4 year old and I am currently pregnant with his first child, the police officer has told me she is going to have to inform children's services... I'm absolutely devastated, he has never done anything to me or showed signs of it and he's been fantastic with my son, when we met he was completely honest about what he has been accused of in the past. I'm in complete shock.
Can I just add, she said when children's services contact me they will probably try and convince me to leave the relationship...I can't get my head around it, he's never done anything to me or my child...and no one else for that matter, he's only ever been accused and when he was charged got found not guilty, how can they this!!