I left at 33, met someone new and had my first child at 36, second at 38. Ex is now 48 and still childless almost twenty years later. In my case, there were other complications in the first relationship. Ex was a lovely person, but with huge amounts of baggage and trauma from his own childhood which I could see made the idea of having children (and normal relationships) very difficult.
The thing is, there’s no guarantees in life and you could fail to get pregnant even with someone who wants kids. It’s a hard choice.
It is a gamble and you have to be aware and ready to live with the other outcome, that you end up without a family or partner and resolved that that actually isn’t the end of the world either.
To be honest, this was the one time in my life I had a bit of a messy cross over. I moved out and to a different city from my ex, but was still visiting him, but met someone online at the same time (who is now my husband). It made it much easier to let go when I knew I was already falling for someone else, but the original relationship was already unworkable.
You’re in a harder position as you’re not mentioning any other problems, however, unless he’s very stupid, stringing you along at your age is an incredibly selfish and duplicitous act in itself. If he says he wants children in the future, just not yet, what he’s really saying is he wants children with someone, just not you.