Help me please

I just started dating this guy, he’s 16, and recently he told me he got his ex pregnant. This happened when he and I were just friends but I’m starting to get a little anxious. I’m scared he’s going to leave me to help his ex out with the baby, even though both of them told me that’s not going to happen. I’m the older person in the relationship and I honestly just don’t know what to do. He’s afraid of losing me because of what happened but I’m more afraid of losing him. WHAT DO I DO TO HELP HIM OUT IN THIS SITUATION??!