Why?

If we really read the same comic you know Dojun did rejecting Jaehee multiple times. It was Jaehee who's persistent one and chase into his college.
Also Jaehee not playing nice by manipulate Dojun' guilty conscience so he can date him.
I think Dojun already tolerate him a lot

I get that the Jaehee? Was stubborn and mulipitive but Dojun did keep going back...

Then he should match his words with his Actions. Because based on what he’s doing he is not rejecting him at all and he has gone to
Him multiple times physically to have sex so no it’s not clear

You mean Jaehee' is keep going back.
Was Dojun suppose to completely cut off relationship after he reject him? I'm sorry I don't understand that kind of logic, it not like they're enemies or something. They were friends before fall in love.
It was common sense on human relationship after get rejected properly Jaehee supposed stop his pursue, but he manipulate Dojun' guilty conscience so he can date him.
Dojun' may not completely innocent because he's kinda pushover but between one who's manipulate and the one who's get manipulate is clear who at fault.
Sorry I don't understand your logic which blame Dojun' of situation. It was very bias and double standard in my opinion

Are you forgetting he were on "contrac relationship"? It was Jaehee who proposed it and At the end of the day it was also Jaehee who's cannot accept it simply as "fake relationship" and asked for more.
Again why you say it as like Dojun' was the one who demanding for the sex?

You guys so biases, basically "It perfectly okay for someone to keep pursuing other no matter how many times he got rejected, and the one who's get pursued are the one to blame unless they completely cut off relationship".
It strange to find many reader's normalize so called toxic masculinity on yaoi relationship.