Am I Being Unreasonable? Original Owner Wants Car Back

I'm not asking much above actual cash I've spent all in the last 6 months. There's no reason why I should take a loss for something I didn't initiate. If he wants to interrupt my progress, he can assume my accumulated position & do everything possible to keep me on the trajectory I've worked hard & paid actual cash to establish. If I attached a labor rate to all the work I've done, the number would be much higher, I'm positioned at just my cash outlays. Is what you're saying by working with him that I should be willing to dip into my pocket to make this work for him?
I think you're being unreasonable, but not about what you think. I think you're being unreasonably compassionate. Cut the emotion loose. It's business. Emotion will get you in trouble by making you make a decision you might regret later. You have the car NOW. You have thrown out a price. Stick to your guns. Even if he were to fork over the asking price, you might never find another one as nice as what you have. You have the CAR now.