I don't think it this that or the other. Looking at the fact you don't require sex to survive. Food and water is one thing but sex is an option. Many of us have tucked away that part of life to look for a bigger picture. Sex is great but it can cloud the path to healing for some. The “keep it up” remark while funny is really just a silly remark. In my situation if there is no real interest in having relations with a certain person it's not gonna stay up. It's a preference not a problem. Remember it takes two for sex.