Mirena

SO has an 18 month old but doesn't want another baby right now. He said he'd love to try for one when LO is 3/4. So that's two years away. Roughly. What birth control would you reccomend? I had the nexplanon from 11/2013 to 8/2015. I don't want that in again. I'm thinking of getting the mirena. But do I need to have kids before getting the mirena in? What other long term birth controls can I get? I don't really want the pills.