Is it time to walk away from my family business after the dynamic has left me feeling 14 again?

I (30M) have about eight years of experience in high-pressure corporate environments. I’m used to the long hours and intense expectations of high-performance settings; hard work has never been the problem. About a year ago, I stepped into my father’s business to help out. By the three-month mark, that help had evolved into a consistent, senior-level role (Strategy, Modeling, Systems) for a company with a ~£10m turnover.

We never had a clean contract. I raised the issue of remuneration almost every month, but it was always deferred: "We’ll sort it," "After this project," "Once things stabilize." When I finally laid everything out clearly, he sent me £10k—but characterized it as a loan to be repaid later, rather than backpay for the senior-level work I’d been doing.

That was the turning point. I realized my goodwill had simply become a convenience. Meanwhile, I’ve drained my personal savings to stay afloat and parked my own independent project—which had real momentum and paying customers—to focus entirely on his business.

The emotional dynamic is the hardest part to articulate. Despite my professional background, when I’m around him, I "tighten up." All the annoying traits I thought I’d outgrown or "gotten over" as a child have resurfaced. I feel like I’m 14 years old again. My thoughts don’t flow with the independence I usually have; I find myself self-censoring and staying quiet just to avoid friction.

The atmosphere is draining. He frequently makes demeaning remarks about the team and complains constantly about staff costs, which made advocating for my own market value feel impossible. I’m stuck in a no-man’s-land: not quite an employee, but not a partner either.

While my salary has finally been formalized at a market rate, the damage is done. I wake up every day with resentment and I go to bed pissed off. I haven’t had a moment of inner peace in a year. I’m 90% sure I’m leaving at the end of March—not to cause drama, but because I need to feel steady again.

I’m trying to look at this objectively:

• Was I naive to step into a family arrangement without iron-clad boundaries?
• Is this a "Founder Trap"? Is it common for dominant founders to view family labor as a "duty" rather than professional work?
• Is this erosion permanent? How do you know when stepping away is a "necessary" move for your sanity rather than an overreaction?

I just want to feel like an independent adult again.

EDIT (MORE CONTEXT):

To be clear, about a week ago finally reached my limit and "flipped out" (essentially laying out everything I wrote above), and they have since done a complete 180. They’ve now offered a formal contract at market rate and have been flooding me with messages about how "valued" I am and how much they need me.

While the money is finally right, the psychological dynamic hasn't changed. It feels like "damage control" rather than a genuine shift in respect. Imo it was never about the money, its blurred lines and not having a voice.