That simply shows that you have a fundamental misunderstanding of sex. It can be nothing more than lust, but it can also be a sharing of love. 

Before I met my wife, I had a relationship with a woman. With her, sex was lust; with my wife, it is a physical sharing of our love.  I daresay that the married couples I know, both gay and straight, would say the same thing. It is truly a pity that you do not experience this in your marriage.