Hello, welcome to HCM. You seem to be suffering from premature ejaculation. You must learn the start and stop technique for prolonging sexual activity. You must visit a psychiatrist who would be able to help you in better way to deal with it in case you need some medicines. As far as you sperms are concerned you can undergo a sperm count and analysis which will be able to find out any abnormality in the. It is advisable to get your wife also checked up to rule out any pathology in her. Wish you good health.

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If you have premature ejaculation it is mainly performance anxiety. You could be stressed. Try to relieve stress. Do Yoga, Pranayam. Get 6-8 hours of sleep daily. Avoid sitting late hours for work. While having sex if you feel you are going to ejaculate, immediately withdraw your penis and ask your wife to press the tip of your penis gently shut. This will help to prevent premature ejaculation. You can do this as many times as you like to prolong sex. Eat healthy. Exercise daily. Regarding pregnating your wife, you need to have sex during ovulation time that is the 14th day prior to the expected date of her next menstrual cycle. Have it around 2-3 days on both sides of the day ovulation including the day of ovulation. This increases the chance of pregnancy. If you feel there is a problem you can get your semen tested at the Doctor's and confirm if something is wrong.