I'm worried that my sexual partner is pregnant, we had sex and using a condom but the condom split. I withdrew straight away without ejaculating. Have I helped at all or will I need to do anything further?

Well pulling out is better than ejactulating inside without the condom,
But there can still be a chance that she could have gotten pregnant from the other fluid that would have been there.

What else is there to do, wait and let her take a pregnagncy test