How to tell him?

So I took a pregnancy test and it came out positive. I have a five month old now and my fiancé doesn't want another one, he wants to wait 10 years, but not like I'm going to do that. I wanted to wait 1 1/2 to 2 years. We have had this talk before after we had the baby and he told me I already know what I have to do. And I don't want to do that. So how do I tell him we are expecting again?