Ok, let's try to make things clear. First of all, I am planning to have a second child. Whether from my husband or from the "new" guy, it doesn't matter. What I really want is a second child.
Secondly, I don't know yet what to do with my husband. I feel annoyed by him to rather large degree, and, as I've stated earlier, lost faith in him. Maybe we will have second child together, maybe we will work out our issues, who knows? But maybe I will go away from him, and therefore I am open to having affair with the "new" guy and having child from him. Maybe I will have lasting relationshiops with the "new" guy, maybe not, who knows?
In the bottom line - a lot of things depend also on my husband, "new" guy, other people and circumstances. It's not something I can entirely plan out.