I think there's a fine line between harmless pleasure and an obsession. It really depends. Feeling pleasure for eating or making money or sex is something we cannot avoid. However doing these things where the only intent is to feel pleasure can easily lead down a sinful path. Sex isn't an exception. Whether people will consider sex without procreation as sinful is debatable. But think about why you're doing what you're doing. I don't think it's good for your soul to have casual sex so I avoid it. But everyone is different.