In layman's term, that would be equivalent to growing up as a man and having an abusive father who manipulate you into thinking men are better than women and it doesn't help the fact that his mother left him. And suddenly finding he's not actually a glorified human being also known as men, but actually a child bearing woman
Don't forget that becoming pregnant and giving birth was also forced onto him. This isn't a story meant to display a healthy relationship. Even in the end Hyesung never truly heals. All his issues get buried with money. And Dojin never comes to understand how much he took away from Hyesung when he was in a vulnerable position. It was frankly gross how he blamed Hyesung for leaving after backing him into a corner.

After rereading this, i realized how dojin's fuck boi past was repressed in my memories because of how good season 3 is. But like, every time i reread this, i can't help but think how heeseung is wrong in both season 1 and 2 (i believe 2 is the one where he kept hyesung in his home). No matter how rational of a person heeseung is for both Dojin and Hyesung, a lot of times, he comes off very insensitive and sometimes cross the line with how insulting he comes off. If you think about it, Dojin bears the responsibility but blames it on the omega.
I forgot this was the kind of story they had
Anyways ppl who hates hyesung really forgot the point that he was bearing the trauma of his fuckass dad who pressures him into everything, and also that fuckass mom who even got screen time with Byul's story (which don't get me started, i hate byul and dojin for treating hyesung's trauma like that). He was literally an alpha* before he knew he was an omega. So him leaving byul after pregnancy, it's understandable given the situations thrown at him.