What you probably should have done is call him out on it right then. Better yet, you should have had a discussion about birth control beforehand and whether you were going to allow him to come in you or on you. Yeah, he should have said something, I'm on birth control and my boyfriend still asks every single time if he can come inside me. Even though its been a year+ that we've been doing it that way. So you are right that he should have said something before he did it, but at the same time you are equally as guilty for not laying out ground rules first and for not saying something right after. It's also your responsibility, seeing how you knew he came inside you, to get the morning after pill, or get him to buy it for you. Unless you are on birth control, which I hope you are because otherwise you buying a pregnancy test with the intent to "scare" him into thinking you're pregnant, may have a result that scares you just as much.