Trying to understand what you have said here: are you saying that life without children is a kind of "death"? Since that was the assignment: to write about death?
I am not sure, as you spend latter part of poem discussing what death was like as your loved one lay dying. Then there is a sort of refrain where you talk again of having no children and how he blamed himself. This poem could be improved upon if you wrote it using some sort of form, separating the speakers. It seems there are 3 people speaking in this poem, right? You, your loved one on his deathbed and the doctor, right? I think this would make a great "Sestina"! For me (and remember, I am only one opinion) the poem needs more editing; more breaks so I can understand what is happening here.