My hubby has the same problem. Try masterbating a bit before sex. it will take down the sensitivity of your dick.

that happens to my guy, but he can ejculate 5 times a day

Psychological factors such as stress, anxiety, guilt, depression, low self-esteem, and fear of sexual failure cause are the major factors of such type of problem. Your partner can help with gradual development of intimacy and stimulation. Such techniques also can help relieve anxiety, fear and other psychological factors and change the mood.
However if you want to increase the time you will have to learn to focus on gradual training and improving mental habituation to sex and physical development of stimulation control. In your pelvic region, various muscles come into play during the ejaculation process. If you can identify those particular muscles and if you can use exercises to develop control over them then you can attain total ejaculation control.
There are some techniques like heart rate technique, breathing technique, training of glans, masturbation and sex techniques.You may find the information about exercises on website