Fiance will only do a threesome if its a guy

Me and my fiance have been together for 4 years, we had one threesome that didnt go well the first time because we both regretted it because it was awkward with the girl we did it with. We didnt plan on doing anymore threeways, but 3 years later (now) we talked about trying another threesome. She said that she would do it with another guy because she didnt want to see me put my johnny into another woman, and then she doesnt understand that I mainly wanted a threesome so that I could have two girls giving head but also make out and all that.

She said she would make out and have sex with a girl but I can only watch which I didnt understand how thats fair or makes sense, but we can do it with a guy?

Now im not against a 3 way with another guy, but I just cant really come to grasps of another guy seeing me naked at times, probably because im not happy with my body. whats your thoughts? Even if we did it with a guy, i know she wouldnt leave me for another person. She is as loyal as they can get.

She doesnt want me to kiss another girl, or eat out another girl. But she would suck another dick and get DP or spit roasted practically.

Thoughts? Obviously we can never just do a threesome.