If you do think he's faked it and want to talk, bring it up gently. Orgasms are super intimate, so you don't want him feeling like he has to defend himself. Getting angry or accusing him won't lead to a productive conversation—and could draw you further apart. Try saying, "Hey it seemed like that orgasm was different than usual" or, "How was that for you? It felt like something might have been off—do you want to talk about it?" Or you could hold up the empty condom and say, "What's this?" But don't say we didn't warn you.
Men fake orgasms, too. How to tell if his O is for real.