Threesome

So earlier today me and my boyfriend were talking and he brought up having a threesome. He said we should try it, it would be fun. He even went as far as to say I could pick with who. I’m just not sure how to feel about it or what to do. Like I’m not completely at 100% no but I’m definitely not at a yes either. I might want to try it at some point but I’m definitely not there yet. I don’t even know how that would work...

I think part of me is scared that it’s bc he wants to have sec with other girls. But then like I look at the fact that I can pick whoever I’m comfortable with. Help. Thoughts. Comments. Suggestions. Have you ever done it? How was it?