Roughly about 70-80% of women never or rarely experience orgasms from penetrative sex. This is due to women not learning their bodies well enough to know what leads to orgasm, not communicating with their partner, or having sexual insecurities. For a long time, the "Orgasm Gap" has led to women faking the Big O.
Women fake orgasms for various reasons. Some do it for the reason stated; trying to avoid hurting their partner's feelings. Others do it out of frustration with their partner's sexual performance to get it over with or to prevent their partner from cheating or leaving. Some women even fake orgasms because they feel pressured to orgasm with their partner despite not being able to. Whatever the reason(s), my #1 advice is to STOP FAKING ORGASMS! You're only cheating yourself. While your partner may walk away in orgasmic bliss and feeling like they've thoroughly pleased you, you'll be dissatisfied and left yearning for more. This, in most circumstances, leads to a buildup of anger and resentment, which causes considerably greater stress in the relationship.
When you fake your orgasms, you are 1) practically lying to your partner, 2) encouraging your partner to continue their normal sexual routine with you, 3) pushing yourself to become more sexually frustrated, 4) driving yourself to eventually become disconnected from your partner (sexually and emotionally), and 5) increasing your inability to orgasm.
You should have a conversation with your partner. Be honest and transparent, and make sure to point out how much you enjoy sex with him (emphasize the things you like most). Also, mention what you don't enjoy. You need to teach your partner how to properly please you. Don't be afraid of guiding him during intercourse. You can also let your partner watch you masturbate. This allows him to observe the way you touch yourself, the speed and amount of passion you prefer, and whether or not you enjoy gentle or intense pressure when nearing orgasm.
Despite what you think (or have been told), faking orgasms never has and never will be advantageous. Understand that it's ok to stop a sexual encounter if you're not enjoying it. Use this as an opportunity to take the lead and guide your partner or to talk about sex (discussing what you want and setting reasonable expectations for you both).
Here are 3 self-help exercises to help you ease into the conversation about your current inability to orgasm:
1) Slowly begin to act more genuinely. This could prevent your partner from being caught off guard when you decide to have the conversation. You don't want to come out of the left field and blindside him after making him believe you orgasmed with him for 6 months.
2) Make recommendations for new things you want him to try. You can create a list of what you want to be included in your sexual experiences. Most women prefer lengthier foreplay to increase sexual tension and arousal and the use of pleasure-enhancing items such as vibrators and lubricants.
3) Communication is key. Maintain open channels of communication. Tell your lover about your preferences (your likes and dislikes). Don't only tell him when something feels good, but also when something doesn't feel as pleasurable. This is the only way you'll both discover [together] what amazing sex means to both of you.