Women do not associate sex with intimacy.
This is an insight borne partly of time spent with Rolo Tamassi's rather Excellent book, The Rational Male (despite the tragically awful audiobook version). And partly of my own observation in my (still somewhat...lackluster, waxing and waning LTR.
We all know women like sex. But I think a lot of us still believe that sex, to women, is representative of intimacy. Of romantic love. And while maybe - and i only say maybe - this is true during the courtship phase, it is certainly not the case once you enter into the Bait and Switch (or Relationship) phase of your time with a woman.
For women in any sort of relationship with a man, sex is about power. Period. Full stop. On your part, sex should express your power. Dominance. Forcefulness. The barely contained aggression of the Raw Alpha Male she so powerfully desires. On her part, sex represents bargaining power. If she is your sole source of it, then she has power in the relationship. Perhaps not total power, but some measure of it nonetheless. If she believes, however, that she is not the sole source - or even that you are capable of readily acquiring other sources - her power is greatly diminished, if not removed outright.
What this means, for men, like me, who for some bizarre reason still choose to engage in monogamous relationships (seriously, just dont, at least not until well into your thirties, if not later) is this: You must never let her believe that you cannot acquire ready sources of sex beyond her. Not. Ever. This is basic Red Pill truth anyway; we all know it, or read it, at least, every day. I cannot emphasize, however, the degree to which this will shape your own relationship, especially once you become monogamous with a woman.
Because the simple truth is this: A man's power is expressed through the act of HAVING sex. A woman's power is expressed through the act of REFUSING sex. Again, basic Red Pill truth. But the manner in which it plays out, and the degree of relevance it carries, in your own relationship is important.
A woman who knows that you simply cannot acquire other ready sources of sex will put her power on full display. She will make Sex transactional, giving it only as a behavior conditioning reward. And then only often enough, and with enough earnestness, to keep you in line. Passion will die. Your feelings will falter. Your relationship will become a place of resentful misery, as you face your binary choices: Incel Existence, or Blue Pill line-towing in exchange for subpar sexual "rewards" doled out like the carrot at the end of a very long stick, to a very tired and dispirited horse who has gone on trudging long past the point where he would really rather take a rest. This will happen because your woman knows she does not have to compete for your attention, or the security and stability you provide.
A woman who remains eternally concerned that you have ready access to other sources of sex, however, must compete for your time and attention. She must EARN you. This makes it much more likely that said woman will see GIVING sex as an expression of power (namely, power over another woman, or the power to win in competition with other women). As such, she will give eagerly and without hesitation, as your continuing to reward her with time and attention is a reinforcement of her own belief in the power she wields. But be mindful you dont slip too far into contentment (the mistake I made) and let yourself go a bit. Because once you do so, you end up with the situation I described above, a largely sexless, carrot and stick existence in which you must tow the line to receive carefully doled out sexual rewards.
So gentlemen, work on yourselves. Lift. Stay lean and fit. Maintain your own hobbies and interests. Make her continually enter into your frame if she wants significant time with you. Acknowledge her. Treat her well. But maintain yourself, control the frame, and maintain enough space and "me time" to always leave her wondering if, just maybe, you could slip away to some other lover. Because that will turn her desire to maintain power in the relationship into a desire to express power through competitive giving of sex, as opposed to the manipulative withholding of it.