It sounds like you really want this guy to fuck your wife but just haven't admitted it. From the way you describe her and your thoughts, I'd want to fuck her too. If I was your neighbor, I'd already be fucking your wife. You have several options.
1. Do nothing and let nature take it's course.
2. When your wife is off shopping, you install 2 hidden video cameras to view on your phone. One that watches the front door and one for your bedroom. So, you can watch for any unexpected action.
3. You invite him over as an interested shopper to give you some ideas and costs to retile the kitchen and bathroom. Let your wife be a part of the selection process. Find out if he does the installation himself.
4. You have the cameras so you can monitor the progress. Because admitted it. You want him to fuck your wife. You probably want to fuck her filled with his cum. Maybe lick her pussy clean. I've been in so many situations where I'm there to does work and get to fuck the wife as a bonus. Even when the husband is watching. Even at parties.
5. Understand this. If he gets your wife pregnant, it's okay. You are party to having her sexual appetite satisfied. You love your wife and the ...... like it was your own. Let him know it is okay and if he wants to have a relationship with the ...... it's okay too.
6. Your wife might be fucking someone else already but you don't know about it. She might be going down the street to this guys house. Be open minded and have a conversation with her to reassure her that you love her and want to enjoy it too. Women have needs and desires that they want to fulfill. Then again, maybe you are a voyeur and want to let her do as she pleases so you can watch secretly.
OR
Tell your wife you want to start a family with her and get her pregnant. So, what are you going to do? I want to know.