Backstory: DP & I have been together a decade, moved in together 5 years ago (we bought together, I sold my own property which I'm now thinking is a mistake). Both of us have DC from previous marriages, no DC together and no plans to. DP earns 6x my wage, comes from money, I am very much working class in comparison. When we bought we did a deed of trust together stating who owned which proportion of the house, he had slightly more than me to acknowledge him putting more in. Everything was fine.
Fast forward a few years, DP came into some big money at the same time I lost my job. He decided he wanted to pay the mortgage off. I protested, but had my arm twisted into doing it. I was in a very bad place mentally and didn't put up enough of a fight. As a result, he told me that my percentage of the house had gone down, to a single figure percent that actually doesn't reflect how much I'd contributed financially up to that point. The agreement we had was updated to reflect it, and I stupidly signed to say I agreed. Like I say, I was in a very bad place in my life and I regret it.
It's been a huge sticking point ever since, and caused countless rows as I've always felt duped, and that I'm a lodger in my own home. Over time those rows have got worse. It now turns out the updated agreement wasn't done properly. DP now wants to get it done legally, so I will have that single figure percent by law. More recently he came into more money, and put a considerable sum into building works on the house so in his eyes his claim on the house is even bigger now. I have refused to sign anything without solicitor advice for myself, which has sent him into a fit that I'm going to 'steal his money' (he had to pay his EXW a large sum when they split, rightly in my opinion, and he is still very sore about it).
We have been in a rough patch for a while for other reasons I won't go into, but this seems to be a make or break for us. I'm of the opinion that he can buy me out easily enough regardless of the percentage I have, so I can go and buy something myself that's mine and that he can't have a claim on. He said if I do that we're over. But is also adamant that if I want anything other than the single figure percent, we're over anyway. He has gone full on narc nasty, and I'm more than aware if this becomes a legal row, he will just outspend me and I could easily end up with nothing.
To be clear, this isn't about money for me. This is more to do with the betrayal I'm feeling that he did this, in my eyes took advantage of me, and if I leave I'm left with very little. He's obsessed with the idea that I'm going to take his money and that I'm a gold digger. Also that I've set up this argument as an excuse for leaving.
I am really down and struggling, feeling like an idiot for getting myself in this situation and tying myself up in knots thinking he's right. I hope I havn't been too light on detail, but I would love to know what others think on this. Please help me get some clarity.