Posted on parenting to no avail so will try here instead.
I have a 5yr old DS with my ex, we were together 2 years, broke up not long after ds was born and I moved out, we had problems before we had DS but ex carried on partying, would go AWOL etc... so I ended it for good. Sorry for the long post, trying to fill in as not to drip-feed.
The past 5 years have been an acrimonious roller coaster (abuse and harassment to the extent of police involvement) but I've always helped to maintain a good relationship between DS and his dad, never stopped access, if anything I've gone above and beyond to keep them together to my detriment as neither of us have family who are willing to help. Despite our personal relationship he has been a good dad and has provided more than adequately, DS is his life and having grown up between horrible bitter parents, I didn't want that for my own child.
I've been in a relationship for the past 3 years (we don't live together yet and he has little to do with DS but they do get along well) and as you can imagine, ex has still not accepted this. He can be a bit Jekyll and Hyde with me, he's generally ok to speak to but at least twice a month he'll flip and send me abuse over messages about various things from child maintenance to my relationship.
Despite what's gone on, we've kept arguments away from DS and he seems to be quite well rounded. He sees his dad EOW, we make him priority and he knows he is loved by both of us. But here lies my problem, in spite of us never really being together during DS's life and me having a very obvious partner, he keeps asking me to get back with his dad! He regularly asks to involve his dad in anything we do or for him to come to our house - I don't know if this is his dad dripping in his ear, but they both deny this.
The weekend I snapped, in the morning I'd had an argument with ex about me wanting to buy DS a separate secondhand bike to keep at mine. It was pathetic and he started attacking me about CMS (which he doesn't pay in full and I don't chase) and then turned it around about how it was all my fault for us to be separated?!? After this - DS 'races' me to put his seat belt on - he told me that if he wins that I have to get back with daddy. I lost it and shouted at him, told him to stop going on about me getting back together with his dad, it will never happen and his dad was horrible to me. I'm fed up of hearing it but I know it's not DS's fault. I wish he could understand just how vile his dad has been to me over the past few years but I would never put that on him and he doesn't need to be poisoned against another parent.
How do I handle this? How do I get it through to him gently that me and his dad will never be together? I'm so exhausted from hearing it weekly, it's not like he's not surrounded by friends whose parents are together and he knows I have a long term partner who we plan to live with in the next year.