Idk if I've said this already. But, anyway will say it now. Hakyung and Yoonsung compliments each other. Hakyung's character is portrayed to be someone who will do anything for the people he loves. He will always prioritise his family. Cos why not.. His mom and even his brother do the same and are very loveable people. They're a set of loving family. He will pull out from his any relationship for the sake of his family. He'll sacrifice it. Now, Yoonsung is the type of person who has every materialistic things. He obviously has good relationship with other people. But the very person he wanted for his life is the one that's not there. His character is already said that once he is set to something, he will push to get it. And he does that with Hakyung who has a lot to weigh on. Hakyung may push Yoonsung away, but, Yoonsung will always pull Hakyung to be with him. Hakyung tends to need a lot of time to take care of things while Yoonsung is the type who will always wait for him.
Also, if you read the novel, in the end, Yoonsung has the power over his family so regardless of whatever the circumstances, his family got no choice but to accept Hakyung as his partner(Yoonsung's loved by his family too yk). If Hakyung is the inferior type, we got Yoonsung who is a dominant type hahaha