Another baby? How would you approach this?

We have a 16 month old son. He is the light of our lives. I'm 32 years old and my husband is 44. Having this child has been such a challenge for us. We've almost lost ourselves in the process, and come very close to divorce. We are stronger now and I feel like we continue to get stronger every day. Somehow I feel like I'm not ready to give up on the idea of having another baby. My husband, understandably, is. He feels he's too old. I'm not sure I'd want another for maybe 2 more years and he feels he'll just be too old at that point. I understand this yet something in me yearns for another. If we didn't have another I'd be happy, overjoyed with the one we do have as he is the most amazing little guy I've ever known. How do I approach this? What would you do? Should I just give up on this idea? I absolutely do not want to push my husband for something he does not want yet I don't want to feel unfulfilled somehow.... and I'm afraid that I may feel that way someday if I continue to deny my feelings of perhaps wanting to explore the possiblility of another.