When you are able to keep your sexual energy for a longer time, you will cultivate a deeper presence. You will be able to conduct more pleasure in your body. This will benefit you a lot while you are having sex. You can take your partner so much deeper than before. 

She (or he) can experience deeper tantric orgasms.
When you are more in touch with your own body, when you are feeling and staying grounded, you will also be able to sense your partner much deeper.
You will be able to see more.
You will see small changes in her (his) breathing, you will sense if your partner is spacing out. You can then slow down and bring your partner back into her (his) body.
Your job is to stay in your own body and also supporting your partner to stay present with you. 

You are there to get to know each other on a deeper level.
You are there to explore each other. 
You are there to take each other deeper. 
You are there to enjoy deep pleasure through each other.
You are there to experience divine sex and bring each other to God.