Rather than seeing him as a child he tells like the only reason Jonak puts up with him is ...

I DIDNT MEAN TO DOWNVOTEE FK ASS THUMBS

I agree! I also though that when Jonak told the story about the priest it made Adian think deeply about whether their dynamic was the same/familiar in Jonak’s perspective, maintaining a loving relationship between them despite not being physical proves it’s not. I think observing Jonak’s love for Ilse changed his way of thinking for the better and made him want to/be able to see things through Jonak’s perspective and not just his own, compared to when he couldn’t understand his brothers affection for human /desire to affiliate with them or when he was alone for that long period of time before meeting him.

So, I agree with the outcome of your conclusion, but I disagree with your reasoning. Let me explain my thoughts.

So, you said you think that Adian believes he is taking advantage of Jonak because of age and biological differences. I don't think that that is actually it. When Jonak tells the story, he explains that the priest was raping a child. The priest was able to keep those kids quite by giving them better living conditions as a form of exchange. These kids, didn't know or recognize that better treatment without any exchange should have been the standard, and that what they were being coerced into, wasn't ok.

I believe that, not age or biological differences, is what caused Adian to pull back. The nightmare he had, was him likening himself to the priest, by his actions of having Jonak sell himself for the betterment of his village. Jonak had no idea what the outcome of this deal was or could be, but accepted it anyway. He gave up the ability to ever be with the woman he loved, to save her from the possibility of dying before her time.

I think Adian is regretting that, because Jonak will now have to live the rest of his life, with what Adian precieves to be, no real choice.

I think that Jonak will have to be the one to properly explain that the situations are different, not by his age, but by the fact that he had set out willingly with the understanding that he was likely to lose his life for the cause. He knew he wasn't likely to survive, but he was willing to do everything in his power to get the outcome he wanted. That's why he didn't fight Adian on becoming his mate. He meant it by his life, that he would save the one he loves, and the village by association. Being able to live, and knowing that she lived a full and happy life, was the reward. He lived to know that that was the case.

Now that she's gone, Adian may genuinely think that Jonak now has to live forever stuck with him, not considering that Jonak may actually have neutral or positive feelings for him.

So, I agree with your conclusion, but I think the reasoning is actually more complex than age. I think it is more on experience and the selling of one's self without the full knowledge of the outcomes of such a thing, just to better a situation that doesn't better it for the person selling themselves.

Also, this could be my own bias, as I actually did go through a situation similar to the child with the priest. I thought the exchange my father offered was fair, but I didn't know that the situation never should have happened to begin with.