It could be, but it seems like he's feeling it too.

we live together I'm not sure how I'd get my own space. he doesn't even want marriage. I mean I've dreamed of that my whole life but I don't see it happening now.

I actually got that way with my SO after we had been together that long and we had a one year old. We actually separated for like a week and I cried the entire week. It made me realize how much I loved him. I felt hopeless and desperate for something new. When you start a family young you sometimes begin to feel trapped in the relationship. Maybe a little space will do you good. You need to sort out your feelings and you can't do that with him around constantly. I've now been with him for 6 years and married for a year and a half with another baby on the way. I can confidently say that I made the right choice by asking for some space to see what i needed. And it was him.