To win over your husband in a manhwa, first, focus on building trust. Be supportive of his dreams and hobbies. And don't forget to show appreciation for the things he does for you.
You could start by having an honest conversation with him and expressing your feelings. Maybe try to figure out what went wrong and work on changing those things.
You could try understanding his interests and hobbies and joining him in those activities. Maybe show genuine support and appreciation for what he does.
Often, it involves showing genuine change and growth. Maybe work on becoming a better version of yourself and let him notice. Also, surprising him with thoughtful gestures or doing things he loves can help.