((((Foreign Soul )))))

I am sorry that you're feeling so alone and unloved. You DO deserve to be treated better. Your description sounds very painful and lonely to me. I hope that you are getting help from a T and perhaps a pDoc as well.
I, too, think that you should end things with your fiance and focus on building a healthy relationship with your son. Not easy tasks, I know. But, it can be done. Especially with encouragement from your T. Going in to work with a counselor with your son could also be very helpful.
Not very long ago, I struggled with my older daughter. She seemed to hold a lot of resentment towards me, and we often got into huge emotional struggles. I was miserable! My ex-hub refused to let her and I go into therapy together...so, I went in to work with a child T by myself and tried the techniques that she recommended. It actually worked great! It did take some time to build a healthy relationship with my older daughter, but I did it.

Getting out of that negative relationship with your fiance would really help you rebuild a healthy relationship with your son. I wish you the very best!

You're welcome to send a message to me, if you ever have Q's too.