I don't think "sex pills" are going to help you out in this case. If you're talking about medications like Viagra or Cealis (sp?) I don't think they will help with your condition. Those medications are for men who suffer from what is called Erectile Disorder, where the penis has a hard time maintaining and holding an erection.
What you have going on with you is an entirely different sexual disorder called PREMATURE EJACULATION and that can be remedied without medications if you follow this simple exercise called EDGING.
It's basically you delaying your orgasm until you feel that you are ready to release yourself at the right time. During your masturbation session, you get yourself to the point of near orgasm....but then you squeeze your penis until the feeling goes away and then build yourself back up again. Do this as many times until you feel the need to release yourself.
There are no sex pills that can cure this its all down to you, if you are thinking a bout what you are doing to her then thats why you are ejeculating to quick, you just need to relax and enjoy the moment.
And edging would be the way to go, and if you go to pegym they have all the info you will ever need on this exercise.
Welcome to the world of getting older!! However, I have found that maybe if I go ahead and release earlier in the day - say, in the shower that morning if I have a date that night where I expect sex to happen, then I don't orgasm as quickly. Try it!