Threesome?

Cynthia • My name is Cynthia but I go by Cyndi! ? I`m 19 years old and in a committed relationship. ???
So my boyfriend of almost a year asked me if we could have a threesome. I don't know how I feel about that. Makes me feel almost like I'm not good enough but he says he just wants to try it because he's never done it before. Thoughts?