My (40/M) Wife (41/F) Accuses me of cheating on her and refuses to listen to the truth. What's my next move?

Throwaway because my main account is linked to my wife and I don't want her knowing I'm posting here.<br><br>So here's what happened.<br><br>Two years ago we bought a house. And with that came a lot of home improvement projects and renovations. So in order to save money I decided I would do a lot of it myself. However I had no experience so I found another guy who has been doing renovations for the past 10 years. His name is Kevin and he was in the same position as me 10 years ago when he first bought his house. From talking I learned he had a 17 year old daughter named grace. She is currently interested in construction and wants to be an architect. So I proposed to Kevin the idea of my son Jake (15) and his daughter helping me with all the projects I have in mind in exchange for teaching them and experience. Kevin agreed and so far it's worked out perfectly. We're close to finishing the house and both kids have learned a lot.<br><br>Jake is interested in business and finance so he doesn't really care about construction but he's learned a lot of new things. Grace however is very smart and has a natural talent for it. She's picked up on things and skills I couldn't even do. Jake and Grace also get along and there's no issues.<br><br>Well two weeks ago my wife got suspicious and accused me of cheating on her with a woman named Pam. I have no idea who she is and I asked her to show me who. She showed me a picture on Facebook of me, Kevin, Jake and Grace at a home improvement store at the time when I was buying new tools. Grace was standing beside me with her arm on my shoulder and Kevin had his arm around me taking the picture. Jake had his arm around Kevin and Grace is smiling at the camera. My wife insisted that Pam was Grace's mother and the woman I was having an affair with.<br><br>I tried my best to explain to her what was going on but she wouldn't listen. I showed her everything about the projects, the plans, the before and after pictures and the house itself. Shown her pictures of me and Jake working on the house, pictures of me and Kevin, Grace and Jake working on the house and more but none of it worked. I asked Kevin and Jake if they could talk to her and she refused to listen. I even offered to let them move in with us for a week so she could see for herself but she said no as well. <br><br>This went on for two weeks with her accusing me of cheating and then a few days ago she came to me with more and said she hired a private investigator to follow me around. And that she had proof that Grace's mother was the one I was having an affair on. I asked her to show me the evidence and she did. It was a picture of me and Kevin going to a bar to have some drinks after work. We went there with Grace, Jake and his girlfriend. <br><br>I lost it and yelled at her for that. She was sending the wrong message to Grace and Jake. And I told her what she was doing was crazy and that she needed to stop. She called the police on me for yelling at her and they came to the house. Nothing happened in the end but Grace and Jake were very upset and Kevin's very upset as well.<br><br>My wife has started a smear campaign online. She's gone on Facebook, Twitter, Instagram, LinkedIn and more to tell everyone I'm cheating on her. I've had multiple colleagues, former classmates and old friends contact me asking me if it's true. She's ruined my reputation and Grace and Jake are upset over the whole thing. They want to stay with their friends for a bit because of the drama.<br><br>Kevin and I are talking about potentially taking legal action against her. It's just gotten too much and it's gone too far. I'm just not sure what my next move should be.<br><br>EDIT: I have no plans on divorcing my wife.