Hotwife fetish

Hello,
I’m writing because I have a sexual fetish. I have the desire to be in a hotwife relationship. My wife and I have been married now for over 15 years,I am happy in the relationship in every way except the bedroom. I only get off when I imagine her having sex with another person.

It started when I found out my girlfriend at the time had previously had a threesome with two other guys. At first I was heartbroken, I thought she was a virgin and planned on losing our virginity together. Well after a couple of days of dismay I began to think about her having sex with two men at once. To my surprise I became strongly aroused. I had never been so aroused before.

It was in college that I met my wife. At first we were just friends. I enjoyed her company and liked being with her. My first impression of her was that she was a normal college girl out having a good time. I would actually get an erection when she would tell me about the guys that she liked. Well as thing progressed we found that we both wanted to be more than friends. Things were hot and heavy at first, lots of touching, kissing and oral sex. Then one day she told me that she was actually a virgin. I was surprised. I also had conflicting feelings. I was a little disappointed that she wasn’t experience but I also looked forward to losing our virginity together.
Strangely at first I was extremely jealous of her. I didn’t like when she had male friends and didn’t like her going out to clubs or parties with her girlfriends. It seemed that the group sex and cuckold feelings were gone.
Eventually I noticed the cuckold desire creeping back into my head. At first it was just imagining her in a reveling outfit in public. The thought of other guys being turned on by her was (and still is) arousing. Of course with all the mixed signals I was sending her I’m sure she thought I was testing her. Then later something happened to really intense my cuckold desire. She invented an old friend to our wedding, an old friend that she had a huge crush on in high school. Well let’s say my imagination ran wild. They spent alot of time together that week. All week long I couldn’t get the thought of her with him out of my mind. It was intense.
Since then I fantasize about her having wild sex. It took me years before I could even bring it up to her because I am ashamed. I know my friends and family would look down on me if they know what I wanted but I can’t help it. I finally admitted to myself that I do enjoy the fantasy. As for my wife she is scared. She admits that some parts of it sound fun, mostly the flirting. She also thinks so of it sounds gross and risky (STDs). She has never been with another man and is also uncomfortable with her body. She also worries about what other people would say. So for now it’s just a fantasy but I’m having a hard time just keeping it a fantasy. Does anyone have any advice? I’m I crazy?