Hi @TiredParent, so sorry to hear that you are dealing with this. I can hear that it puts you in a really difficult position and you are left feeling hurt and worried for your son. I can see why you are feeling concerned and are wanting to step in to make sure that your son is not in a harmful relationship. I assume you have but just to be sure - have you talked to him about how she has been controlling in the past? If you have already made your opinion known, it is a tough one. Whether you agree or not, your son is likely to pursue this relationship, especially if he is interested in her. The only advice would be to listen to him openly without judgement, so that if she is controlling or abusive, he will be comfortable coming to you. You can also try to have a more neutral viewpoint or voice your concerns in a way that is really respectful and sensitive of his autonomy. I know it can be hard to do this as a parent but it goes a long way in your teen being able to trust you. It will also help to show him that you will be supportive, even if the truth is not something you want to hear. I am also wondering if you have thought of talking to a professional, either for yourself or your son? I imagine this must be really hard on you 
I hope you're able to find a way to look after yourself throughout this.
Hi @TiredParent thank you for sharing with us here on the forums.
I'm sorry to hear that so much has happened recently with your son. I can hear just how much you care about him and just how worried you are. I can only imagine how confusing it must be for you to wonder what he must see in her after being against her for so long, especially since hearing the experiences from the ex boyfriend. That must be such a difficult thing for you to experience. I am just wondering how you are looking after yourself during this difficult time? It's important to practice some self-care to make sure that you're getting through this too.
You mentioned that you have not spoken to a professional about this, I was wondering if you would consider a helpline? One helpline that you can call for advice is Parentline. You can call them to talk to a trained counsellor and get some advice around what your next steps should be.
We are all here for you
