Responses
I think in this story they only reject when the omega is in heat.
He was literally puking when they were having sex as his body rejected the seme. That's why he kept assuring and urging him with his words. I think after all the time after they get married maybe his body is used to having sex with "wrong" person, so it doesn't reject the seme anymore
The fact kei was marked by an alpha and could still hav s*x w tsugitsugu made me super confused...i thought the body automatically rejects everyone else. The story is really meh