ADVICE PLEASE!

Im married. My wife was asked by her male coworker/friend to join him in looking into buying his first home. I thought it was an unusual request seeing that it is a very personal matter (one that you’d typically share with a family member not a coworker). I shared that it made me uncomfortable for her to go because I’ve had a gut feeling for a while that he has feelings for my wife. My wife said she doesn’t think so & that it’s not weird of him to ask her at all. She said I’m “controlling” and refused to talk about it any longer. I told her I felt disrespected as her partner for dismissing my feelings & told her I would leave because it isn’t the first time we have argued over him. Maybe she needs to reevaluate things if she doesn’t want to be with me, or have respect for our marriage. She left with him yesterday & has been trying to kiss a$$ since she got back because I’m clearly upset. I don’t know what to do. I mean, am I wrong? Am I not understanding how marriages work, or is it her? 😞