Oh no, only not sperm bank. It's important for me to conceive child with someone I love. I want to tell a child that I loved his or her father, which would be true. And it's also important that child knows genealogy, ethnic identity etc. I can't take away that thing from my child.
As I wrote, paternity wouldn't be a secret to no one. Maybe it could involve hassle with relationships, if they are negative, but I think it's worth it.
Of course, I need agreement to conceive a child, but I think I would get it in any case. My husband's agreement is without question, he was himself talking about "sister or brother" to our son. And the "new" guy also was talking to me about having a child together.