Time machine. Go back 8 years ago and make it clear to your husband that the tree goes or you do. We know of no way to keep seeds from going where they wish. And sprouting. And damaging your wooded area.
We would begin by going to the source and getting rid of the original tree and any others that have sprouted. Then, vigilance. You will have to learn what the early seedlings look like and snatch them out of the ground as quickly as they sprout. This could take years, but compared to the damage they could do to the wooded area, you will probably feel it's worth it. Here are some previous answers on Paulownia from Mr. Smarty Plants. We are sorry you didn't find us 8 years ago when you really needed us. Each link has others and some may be duplicates.