Should I stay with my Boyfriend?

I am struggling to decide if it is time for me to walk away from my relationship. I am 30 and have been with my boyfriend for nearly 3 years. He is from Italy and I am from South Africa. We meet when we were both traveling in London. I always thought I would go home as I am really close with my family, although not all of them are still in South Africa. So when we started to get serious I told him I would never move to Italy and if he knew that he would never move to SA he should tell me and we would end it then. He said he never thought of living there but wouldn't rule it out. That was all I really need at that stage so we continued on and have a great relationship. My boyfriend has always wanted to move to America. But that never really seemed like a real option. We had a major fight and I said whats the point in working this out if we cant agree on where to live in the long run? He said then he didn't care where we lived as long as we were together. Then America became an option for him and everything changed, previously he had said he knew he wanted to be with me forever but when I could sense something was up and pushed him for an answer he said that he didn't want to marry me just because I agreed to move to america with him and that he wasn't sure he wanted to get married ever. I know he was really stressed at the time so I let it go. He has been really supportive financially and emotionally to try and get me to America but its such a long process. And there is no end in sight. Which means we are going to have to do long distance and I am going to have to do extra schooling so that I can work in America. We haven't talked about where our relationship is going in awhile I think partly because I'm scared. He occasionally says 'oh but what if I want to go back to Italy' and that really isn't an option. I don't speak the language, I couldn't work and I couldn't make my own life there. Plus his family aren't as close as mine so I just don't think that's fair (even if that sounds childish). I feel like I am giving up so much for someone who gives me the impression he's not sure if he wants to be with me in the long run. When America first came up I decided if I didn't try I would regret it but I'm not sure if that's still true. I want to get married and have kids and I feel that I am running out of time. I know it sounds silly but statistically getting pregnant when you are 35 or older is harder, with more risks for you and the child. And I want at least 2 kids and 5 years isn't a huge amount of time. I don't believe in soul mates in that I don't believe there is just one person for everyone but I love my boyfriend and would love to have a family with him, I just don't know if that's an option. He has lots of commitment issues, he had an unstable family life as a kid and has no good relationships within his immediate friends and family that he would want to mirror. So he thinks things like I am going to give him an ultimatum to marry me but for me that's just not what relationships are about. I will walk away before I ever give him an ultimatum. I am so confused. What should I do?