Sex is mostly touching and not visual. That's why people can have sex in total darkness and enjoy it with each other.
If all you have is just the visual effects at a distance, then this is just another way of experiencing porn. Which is a 3rd person point of view kind of experience. You cannot participate directly in it.
To include the feeling of touch with virtual reality, you need to have a robotic doll that feels the same to human touch as human body does. And this kind of technology doesn't yet exist. It probably is possible to make the sexual behavior of a robotic doll similar to human behavior. But making the doll feel to human touch as if it's a human body is very difficult to do. This kind of thing isn't yet possible now.
[Link]