Talking about marriage and kids

Mo
Last night my boyfriend and I had a date to talk about our future and our thoughts and plans. We have been dating for 2 years and are really happy. 
We talked about marriage. I said I thought it would be nice if we could talk about it and not feel weird. And he said it would always be a little weird. But he said he likes the way I go about it when we do talk about it. How I never include him as part of the wedding I just say "some day when I get married..." or "well at my wedding..."
Before that we had talked about kids, and we both want to move out and travel and go on adventures together. We both were able to agree on our future and how we felt about children In particular OUR children  
We discussed how we wanted to tread lightly on these subjects because there was a possibility of scaring the other person or hurting their feelings. 
I told him I love him and would be happy to have his children and he said if it were to ever happen he was be ecstatic and that someday if it were to happen it was be a dream come true.  But we couldn't talk about marriage! Like we barely discussed it. He gave me so many opinions on children and didn't really say much about marriage except what I mentioned above. 
He said it was hard to talk about because that's such a huge commitment. And I said "well the idea has never bothered me. I have absolutely no fear of commitment" 
And he said "yea me neither" and I said "that's one of the many things I love about you"
He's 23, im 21. Did any of your husbands act like this while dating? Is it possible he's just afraid ? How do you know when a guy is ready ? I have a million questions. Just. How did your husband act about marriage when they were just your boyfriend?