Husbands side chick

So my husband and I separated for a couple of months. In those couple of months he was seeing a girl. This girl says she’s pregnant with his baby and she’s moving out of state. She wants him to be in that babies life but doesn’t even know if it’s his. She thought it could be his or her baby daddy. He says it’s not but I’m so lost of words right now. Now that him and I are back together I am so lost for words. We are still so rocky with our relationship and this just puts so much more on it. Advice please?