Men are a bit masochist- that's why they want to know if the orgasms women have are real or fake. They won't say ''this girl is faking because she is thinking of me.'' He wants to learn if the orgasm is fake or not and wants to get sad over it. That's probably the reason why he asks ''did you come?'' after having sex.
Even though the women having sex with you don't have to fake anything, there are a few ways you can know if she's faking it or having a real orgasm.