My approach to sex was based on the ideas of Rav Yaakov Emden in his Sidur.

Sexuality is the center of life. Not reducing it to the basement of the human being deserves study.

 And it is not simple. Mainly you need a Neo Platonic idea of the world in the first place which people don't have anymore.

You need a concept that sex between a man and his wife does great corrections in the higher worlds and the more holiness in that relationship the more corrections are done. If done with attachment with God, sex is the highest divine service. But if a person is not attached in his soul to God, then sex  loses its holiness. So according to the degree sex is removed from this standard, that is the degree it loses it holiness and becomes a tool of the Sitra Achra, [the Dark Realm].

My approach to sex was based on the ideas of Yaakov Emden in his Sidur. That is to sanctify oneself before the act and during. Especially when conception is possible. [Read the Sidur, I do not want to be a spoiler, but the main idea there was when conception is possible it it must be after the exact  middle of the night and only on Friday night. That is when holy souls come into the world.] That is you have to calculate the exact middle of the night of Friday night and go  to the mikvah or a river or lake and pray to merit to bring in holy souls into the world.
[The way to go into a cold river is to take off your shoes first and dip you feet into the water.Then draw out your feet. Then the pants, and to go into the water up to your waist. Then leave the water. At that point the body knows that you are going into cold water so it automatically begins to send the blood into the inner region of the thighs, and the outer areas become used to the cold. Only then do you take off your coat and shirt and go into the water only once [as the Rambam said.] Also your feet need to be not on the snow or cold ground, but on a towel or other piece of clothing.