Hiley, first of all your feelings are perfectly OK. Really, it is completely understandable how you feel and never feel bad about this.
That said, now more than ever, great communication is incredibly important between you and your partner. If and when you feel up to it, I believe that talking to your partner about how you feel would be so beneficial to both of you. Tell him your feelings and find out how he is feeling. If both of you love each other try to talk about it. This is not the easiest task, but I believe it is necessary. I have found that it is not always good to keep everything inside. Tell him how wonderful it is that he may once again have a relationship with his other children, but also talk about your concerns. These are not silly concerns and he should understand. After all, you are not attacking him, instead you are mentioning this because it has really been on your mind and you are struggling because you love him and want to show how you feel.
Who knows, maybe he'll see where you are coming from and include you in conversations he has with his other children or even his previous partner.
Every relationship has its hurdles, but I really believe that if both people love each other, they become stronger after every situation. Communication is soooo important.
I hope all goes well
