Should I give into my ex's wants?

Me and my ex meet my sophomore year of high school, he moved from NY. He was a freshman in college when we met. He was the first guy to treat me like a princess. We've known each other for almost 5 years now and we've been on and off. The reason being is Bc I want kids in the future I've always wanted kids... And he doesn't.. He tells me if I ever got pregnant he'd leave the country. After we broke up the 3rd time he told me if I had sex with anyone else he didn't want me anymore. Obviously being on and off then not talking to him for over a year I did, and he knows I've dated other people. He hasn't dated or been with another girl in the 5 years... Which confuses me... Any way point being. I want kids one day and he doesn't, he says they are to expensive and a waste of time when we could be traveling the world.. The problem is I don't even know if I can have kids, I want to have a life with him but I don't know if giving up what I've always dreamed of having is worth it... And I don't know if he will ever come around.. I am 19 he is 21. Should I really just give up on a life with him Bc he doesn't want kids or should I respect what he wants and stay with him..