I don't think Adam would care if it wasn't his baby and it was Eden's, because he's already aware that you're dating Eden. So it would be odd if he were to react negatively to you getting pregnant by his dad.

However, if it's his baby and not Eden's, I think he would feel a thrill he would never admit to, knowing that it was his seed that took root in you and bloomed another life into you.

I also don't think Eden would be the type to ask for a paternity test since he's not really aware of your promiscuity in canon, I believe? He accuses you of slutting it up when he sees you wandering town after not coming home for a while, but he gives no other indicators that he's aware. Not to mention how Adam's son would most likely resemble him enough for him not to question whose baby it is.

Which is a relief for Adam's freaky ass. He also still wouldn't use condoms after all this.