13 year surprise!

My husband and I have been together for 13 years and have 2 kids together. When we first started dating, I asked him if he had any kids. He said that a few years before he was with this girl, she cheated, so he broke up with her. Months later she claimed to be pregnant and was giving the baby up for adoption. He never heard from her again and moved on with his life. But now the adoptive parents are reaching out to my husband saying that he has a 13 year old daughter that would like to meet her half brothers!

I know I sound selfish but I'm devastated that there is a possibility that he has a daughter. I thought it would always just be OUR family and nobody else would come into the picture. And it hurts that he told me it was YEARS before we got together, but was actually only a few months!

To go any further there needs to be proof that he is even the father. He says she was with multiple guys at that time, but has only mentioned my husband as a possible father.

This is so hard on me because it's completely out of my hands but envolves my entire family.

Another slap in the face is that I've really been wanting another baby and he knows that, but now this comes up out of nowhere, so he doesn't want to even try to have another baby. Any advice?