guidance

Can someone explain and or guide me where to find and give me terms for women who are the ones who with consent get to cuckold there husband with as many people or whenever they want JUST LITERALLY WHAT THE TERM FOR THE WIFE BEING IN CHARGE AND BEING FREE USE AT HER OWN REQUEST AND THE HUSBAND...

Context: I'm 28, my girlfriend is 23. We've been together 5 years and I'm the only guy she's been with sexually. We're in the UK. I first brought up the idea of involving another guy in our sex life about 6 months ago with talk of a threesome. Not going to lie, I was hoping that this would lead...

My dick is really small, I think I'm only an inch and a half long. My wife has a really big ass and literally I have trouble getting past it to try to have sex with her (doggy) and I always slip out just due to my small size. It really is over for guys like us I think. Any other guys?