I’ll try my best - I’m having a hard time trying to express what I’m thinking.
Good sex is a tribute to yourself and your partner. It is a very intimate experience - you are allowing someone else to be a part of your life and an extension of yourself in a way you wouldn’t allow others to.
For women, you are quite literally allowing someone else to be a part of yourself, and there is a big element of trust and vulnerability which comes with that.
For men, you are expressing love for someone physically, while also celebrating yourself and your character. People have all different kinds of styles to do this in, but generally there is an idea of masculinity which you are embodying. Traits such as strength, courage, decisiveness, and trustworthiness come to mind.
Sex is ultimately an act of reproduction, in the purely biological sense. It doesn’t have to be used just for reproduction, but the possibility is always there. For women, reproduction is a very costly and time consuming thing which ideally is done with a partner that they love and trust. This will always play a factor in sex.
When you make this connection with someone, it’s permanent. You will always know them on that deeper level, no matter if you never see them again, or if you get married. For most people, making a ton of these connections and having them all leave after is incredibly psychologically damaging. You start to either undervalue yourself, or distrust others, potentially both. This isn’t as damaging for men generally, but it’s a pretty universal possibility.
In many ways, we are spiritual beings, and our physical actions are a representation of our values. I’m not trying to come across as a prude - I unfortunately understand the spiritual power of sex and the danger of bad/frequent connections because I’ve had experiences which I’m not proud of.