Boyfriend avoiding marriage

I'm 30, my boyfriend is 37. We've been together for 3 years. We have a month old daughter together, 5 kids total between the two of us. At the beginning of our relationship, we both discussed the fact that we wanted to get married. He still says he wants to get married, but we're not. We're not even engaged. He says he wants to go to Vegas to get married, but that's so unrealistic. We'll never be able to afford it. I feel like he makes excuses to not get married, and is only saying he wants to to keep me happy and around. How long would you all wait for that?