Sex/ disappointed

So I decided to buy some lingerie, to look sexy and get a reaction out of my boyfriend. Bought it showed it to him. He said he liked it. Then I spend the night at his place put it on for the first time. I was going to surprise him, he didn't know I had it with me. I'm wearing it he walks in the room doesn't look at me, I am just standing behind him. I giggle abit because I'm giddy. So he turns around and says oh I'm sorry I didn't see you. Then proceeds with what he is doing and just ignored me. I waited he didn't do anything. He left the room I changed and that was the end of it. So now I'm super sad and disappointed. :(