Boyfriend wants threesome...

Okay so me and boyfriend have been dating for a month now and he said that he might want to have a threesome. I never had one before and tbh idk if I really want to bc I don’t wanna get jealous over the fact that he would be fucking another girl. Also he wants me to find someone to do it with and idk if I know someone who is down for that. He said he’s not gonna push for it but “it would be nice”.

What do I do in this situation?