You are suffering from "PRE MATURE EJACULATION".
It is a very common problem which is treatable.It may be due to sexual excitement, some anxiety
and over stimulation.After ejaculation,body becomes relaxed and it may take 1/2 to 1 hr to arouse again with erection....which is normal. But you have to rule out underlying pathology (like hypertension
,any anatomical disorder etc) for PME and if no pathology is found,then follow guidelines.
1) Relax more..problem reduce
2)When your arousal level is high and climax begins...distract your mind from that and think for somethings with deep breathing
3) By Start & Stop method: Near climax withdraw your penis from partner and relax enough to prevent ejaculation...helps in long sex act
4) By Squeezing: Your partner squeeze the end or the tip of the penis for 10 to 20 sec when ejaculation sense , withholding stimulation for about 30 sec, then continue stimulation. It can be repeated until ejaculation occurs.
5) By applying local anesthetic
cream or by thick condom to desensitize the end of penis..helps in long sex act
6) More Foreplay: stimulate your partner more & more to high level of arousal..then intercourse..ejaculation and orgasm occurs in same time
7) Practice diff methods of masturbation
to know your feelings and sensation
So you practice above things and get a good result.
All the best.