OK, this is going into some treacherous territory, so hear me out. Yes, open and honest communication is the key to maintaining healthy sexual relationships. Yes, you should not disregard your own pleasure for the purpose of appeasing a partner. And yes, you should have as many real orgasms as you please. But sometimes life gets in the way of these ideals, and there are occasionally times when it's OK to fake an orgasm.
Now, you should feign the Big O all the time. If you’re regularly having trouble reaching climax in sex, then this is something you and your partner should discuss openly and work toward remedying. (For instance, you may want to try some of the sex positions that are better for achieving female orgasm than others.). And "training" your partner to believe that certain moves will get you there when they don't will only hamper your relationship. But there are times when, for whatever reason, you’re just ready to get things done and go about your day while sparing your partner’s ego. If you just decide to pull off a fake on occasion, then you probably aren’t doing much damage to your sex life. Sometimes it’s just the easiest way to bring the evening to a close, especially on occasions when your mind is just not in the game. It’s just a holdover move until you and your SO have the time and energy to get you to the real thing.