If you're willing to put in the time and discipline, you can train yourself to last as long as you wish. The first step is to find you PONR, (point of no return) and practice just reaching it and then backing-off. Do this over and over until it's mastered, (yes, this is done solo unless you can find a willing 'trainer') and when you feel you have this part under control, you can do an exercise called 'edging'...essentially finding that place where you can continue with stimulation right before orgasm and ride that 'edge'. Practice with and without condoms. Good luck!