Your reason for faking an orgasm is a common one for women. In our orgasm-centric society, people tend to inaccurately equate orgasm with satisfaction. What is most likely to prevent an orgasm from happening? Focusing on having an orgasm rather than being in the moment! So this is a feedback loop that is hard to escape. Your partner thinks he is being an attentive partner by focusing on your pleasure, but this is actually detracting from it.
I would start explaining this situation to him by simply being honest. Start with a compliment – tell him you really enjoy sex with him and maybe even be specific about something you particularly love. Tell him that you find sex satisfying without an orgasm, and that if you feel pressured to orgasm, you’re not going to orgasm. If you approach this from the stance of trying to improve your sex life and, in turn, your relationship, he should be receptive to this feedback.
