Talk about kids but not marriage

Me and my boyfriend have been living together for a year now and he's so open to talking about having kids with me in the future. We discuss how many we want, how many years down the road we will want them, things like that. But he has never once brought up the topic of marriage. I know we've only been together for a year but we both know we are the one for each other. Not sure how I feel about him talking about kids before talking about marriage? Thoughts?