40 [M4A] NC/Online - Thinking I might be a cuck? Trying to figure it out!

Hey would love to talk to men, women, or couples who have some experience with this fantasy or lifestyle. I feel like I check all of the boxes. I'm bi and sub with men. I'm very small and I fantasize a lot about seeing my partner with other men. How do you know if it's just a fantasy or something you could actually go through with?