Why am I not geting pregnant is it me or him how do I know were both n our med 20s married for 3 years help?

Could be either/both. Infertility in a minority of cases is due to a male issue (low sperm count, poor sperm morphology, etc) and the remainder are due to female issues (blocked tubes, no ovulation, etc.) generally the first (and easiest) place to start is to do a semen analysis. See your doctor to help you along this process.
Getting Pregnant. Successfully becoming pregnant is about a man's sperm reaching a women's egg, with the fertilized egg attaching to the lining of the uterus. There are generally four reasons for failing to become pregnant: sex when the egg is not present, insufficient or bad eggs, sperm that are not motile, or inability for the fertile egg to attach to the uterus. See an ob/gyn doctor.