Over react?

So my boyfriend and I have talked about a threesome a few times in the last while and it’s his birthday weekend. Since he said he was down to do so, I started looking as a surprise gift. But when I told him about it. He got mad at me saying it’s cheating, that he only said he was down because I want one.

I didn’t know he was only saying that cause it’s what I want. He’s barely talked to me all day and we’re having a small party for his birthday tonight. He can’t just avoid me all night...