Sex with wife better because my idiocy, fears, character, humor, strengths, past, etc. are apparent to her and I am more naked before her than I am with a woman I am paying to have sex with me. Likewise, her idiocy, fears, character, humor, strengths, past, etc are more apparent to me and she is naked to me.
This produces opportunities for great interpersonal tenderness, mercy and warfare and is much more erotic by far. Very rarely does one feel anything approaching this tension with a woman you are paying to have sex with you.