The issue (not a 'problem') may be psychological (self-implied pressure) or just physical (sensitive knob), but if you know you will be having sex, like P4P, you might masturbate an hour before (get a love hotel early and enjoy the TV!). You might also get your unoccupied hands on some Viagra or something to pump yourself up a bit (confidence and knob) for a session. After six months of that, especially conditioning your knob to sensitivity, drop the pill and see how you go. Also, tell whoever you are with that you are a bit quick out of the blocks, recognise your own signs of ejaculation, back off and work on the gal instead - work it into how you conduct a session. Or, as someone said on the site recently, think of Leonid Breshnev in his underwear.