Welcome to the forum! You’ll find this is a (mostly) very friendly place to engage in frank discussion, share fantasies, and ask for advice. You’ll generally get better engagement by contributing to an existing topic (this would definitely add to the conversation over at “What’s your fantasy?”
In the meantime, as others have shared: these are not unusual fantasies at all. I don’t particularly have a cuck fantasy, but I do love seeing exactly how far my wife can go with larger toys and dildos and we talk frequently of threesome/group/swinging fantasies that will stay just that.