Ask HN: Cofounder Exit Offer

I had 15% vested over two years of a seed startup operation. 100k in funding at 9m valuation. 50k arr. We started to disagree a lot, to the point of planning a split. The cofounder who wants to keep the company wants to take back 14%. On grounds of for cause termination. I was open to giving back some equity but this seems like a lot. Thoughts?