There are products available in every pharmacy that will assist you in your staying power. ManDelay is one product; just a small amount applied to the head (glans) - wait a few minutes and it will slightly numb the area. Use something of this sort, along with Kegels and practice the "Start-Stop" method to train yourself to recognize the "Point of No Return" which is the instant ejaculation begins. There are many websites available which will explain this in detail.
Just know that you are NOT alone in this problem and it CAN be corrected. It will take some patience on your part and your wife's, but it can be done. Satisfying sex is not something we are born knowing - it is learned.
Good luck!!
If you are finishing sex before your wife is done there WILL be a problem in the marriage. At one time in my life that was taking place. I was upset,frastrated,it came to the point where I stopped having sex----i was thinking what for,i'm not getting nothing out of it.Then we talked about things we could do, There are sex toys you could use on her,your mouth/tongue, the fingers, please her that way and the sex in yr relationship will get amazing!
Search words premature ejaculation, you will find many website to help you. Learn kegel exercises. You may kegel each other. Kegeling can give you control on you ejaculation.Kundalini yoga is another technique which will put zest in your sexual life.
If you can help her to masturbate somtimes, she will get sexual satisfaction.Counselors can advise you properly.Sexual needs of a woman should be taken care of.