There are alot of ways around this and things you could do if your partner is willing to work with you........if you can go again and again--then no probs.........but if you can't there are things you can do with or without your partners help......such as when you are getting close to cumming...back off a bit, stop stroking or whatever it is that you are doing and then return after a min or 2---basically train yourself.....
That's something you get better in time, practicing a lot with some nice white pussys that are willing to help you improve. After a while you'll be fucking them with absolute control.