My bf asked me something that has shocked me?

He says he needs p***** and he wants to f*** another woman and me to f**^ another man. He said we can tell each other about it when we see eachother again He told me a while ago that he likes threesomes but I thought he was joking We are long distance and I was I'll not long ago Why would he do this is this just a normal fetish thing Sorry for any rudeness but I wanted to say his exact words