Boyfriend advice!

Okay so here's my story. I've been with my boyfriend for almost two years (our two years is on Nov 18th). We have been living together for about a year. I am 22 and he is 25. He is my soulmate and love of my life and I've never felt this comfortable with anyone in my entire life. He is my best friend and he says all the same stuff about me. This is where it gets confusing. We talk about marriage and our future together. He says he wants to marry me and have kids and a family with me which is obviously what I want. But last night we were at a Halloween party at my friends house and he got absolutely trashed and he was going on about how he doesn't want to be engaged right now because he's scared of committment and is scared to commit to me. I am having a hard time figuring out what he wants. When I ask him why he isn't ready he says I don't know. I'm just really confused and could use some advice from you ladies!