Children...😕

So my husband and I have a son and I want more children...at least one more. After we watched our niece it turned my husband off from having more children. Now he hardly has sex with me in fear that I might become pregnant. He says things like I'm too tired or I don't feel good to avoid sex. Or just ignores all of my signals. How do I help him see my side of things? How do I help him understand that I want to be a mother to more than just one child. He thinks that more children will complicate our lives but truly it won't. I don't understand and it's very upsetting. He knew before we ever got married that I wanted kids and now that we have one he's set but I'm not. Am I supposed to compromise and give up my hopes of having another? I just don't know how to proceed. Every single time I bring it up he changes the subject. I just want him to understand where I'm coming from...