What kind of bug is this? We live in Dayton Ohio, and have seen these bugs mating.
Montgomery County Ohio insect identification
Probably a wheel bug /Arilus cristatus. It's hard to see exactly because the photo is straight down on it but I think it's got a "wheel" sticking up out of its thorax, right? Compare it to the photo in the website below. It is a type of Assassin bug which is in the famiy Reduviidae which is in the order Hemiptera or True Bug.
My wife asks if this is a good bug or a bad bug)? She has many plants outside and she worries that the bug will eat her plants.
They are predators, so they eat insects, not plants. You could check Wikipedia: