I think my child's father gave me an STD

So I was engaged to this guy who I thought gave me an std. Since leaving him, I have become pregnant. My ex fiancé just sent me proof of him having no STDS, since my accusations. That leaves it only up to my child's father. Idek know to feel. How do I bring it up to him? What if he didn't know? But what if he DID know?