Sex need advice pls

So I recently got back with my boyfriend who I have strong feelings for. He isn't my baby father but he's accepting me and her. My child real father is a dead beat and doesn't want anything to do with my daughter even after I still told him she's going to be girl. But anyways? My boyfriend wants to cum in me but is afraid imight get double pregnant lol. Is that possible? Is it wrong if he cums in me while I'm pregnant wit someone else child? Advise pls ladies. My boyfriend is a really good guy I swear.