New advice(bit of a rant)

Niamh
Found out I am pregnant a few days ago. Iv known my partner for 5 years but wev only been together about 4 months. This was unplanned but I am happy. My partner has twins with an ex girlfriend, and hasn't told her that were even dating never mind pregnant because he fears she will stop him seeing the twins. There's no feelings going on with each other but it's the case of another woman being in her kids lives that he knows she won't like. He told me last night that he doesn't plan to tell her about me being pregnant until the baby is here. I can't help but feel like a secret. Or that my baby isn't worth talking about. It's really upsetting me and stressing me out, as he said he's not planning on telling his 3yr old twin girls until there brother/sister is here either. I'm frustrated and annoyed and I just don't know what to say or do. This is my first baby and one I never thought I'd be able to have. Any advice or anything is greatly appreciated xx