Maybe is is not the right moment for him to have children. Men start thinking about children when they are ready to provide everything for them - home, good education. Your husband may feel insecure in his job now, or just emotionallynot ready to become a parent. You should talk to him and understand what is the issue.
Not at all! I know of childless couples who are very happy together. However, there is certainly some discrepancy here with regards to you wanting kids and your husband not being open to it. Try to talk to him, get his opinion on the matter. Having kids can be a joyful experience but is also the most nerve-wrecking thing you will ever do, so he might be worried about that. Perhaps the time is not right yet, but discuss it with your husband!
In my honest opinion, a healthy marriage is not dependent on having children. In fact, it is proper communication and shared goals between spouses that is part of whether a marriage is healthy. Perhaps before getting married you did not discuss this topic with your husband. Now is the time to do it and find out what is the real reason for this resistance to having kids.
Many married people stay together happily without kids, but the choice must be one that both parties agree upon. If your husband doesn’t want kids but you do, this will be a source for ongoing conflict and underlying tension in the relationship until you come to an agreement that works for you both. There could be any number of reasons why your husband doesn’t want kids, and you should try to have open and honest discussions about those reasons without arguing. If it seems impossible to discuss on your own, consider seeking help from a marriage counselor.