You do know that seungyeon was just worried for his wife right? They had hoyeon before when they were still young and they had no idea what was going on at that time. Now that Hosik experienced childbirth they realized how hard it is and if they had the choice they wouldn't want another child again but another surprise pregnancy happened. There's nothing wrong that seungyeon asked Hosik, he's just worried that he might not make it through this time. At least he asked Hosik's say about the idea of aborting the child, be annoyed if he forced Hosik to abort it but at least he respected Hosik's decision